diff --git a/.flowconfig b/.flowconfig
index a9265c30608..7da4b2c464f 100644
--- a/.flowconfig
+++ b/.flowconfig
@@ -35,6 +35,13 @@ node_modules/warning/.*
 [untyped]
 .*/node_modules/@react-native-community/cli/.*/.*
 
+; TODO: Remove this line when RN v0.64 upgrade is complete. We took
+; Flow from v0.122 to v0.125 before finishing the upgrade, to more
+; gradually handle the deprecation of `suppress_comment`. When we did
+; that mini Flow upgrade, one error in RN's code was flagged, and it
+; was in this module.
+.*/node_modules/react-native/Libraries/ReactNative/PaperUIManager.js
+
 [include]
 ; Effectively this line warns Flow that this path might be a symlink
 ; (because the developer might be using `yarn link` to have this point into
@@ -115,11 +122,5 @@ module.file_ext=.js
 module.file_ext=.json
 module.file_ext=.ios.js
 
-suppress_comment=\\(.\\|\n\\)*\\$FlowFixMe\\($\\|[^(]\\|(\\(<VERSION>\\)? *\\(site=[a-z,_]*react_native\\(_ios\\)?_\\(oss\\|fb\\)[a-z,_]*\\)?)\\)
-suppress_comment=\\(.\\|\n\\)*\\$FlowIssue\\((\\(<VERSION>\\)? *\\(site=[a-z,_]*react_native\\(_ios\\)?_\\(oss\\|fb\\)[a-z,_]*\\)?)\\)?:? #[0-9]+
-suppress_comment=\\(.\\|\n\\)*\\$FlowFixedInNextDeploy
-suppress_comment=\\(.\\|\n\\)*\\$FlowExpectedError
-suppress_comment=\\(.\\|\n\\)*\\$FlowMigrationFudge
-
 [version]
-^0.122.0
+^0.128.0
diff --git a/flow-typed/@react-navigation/bottom-tabs_v5.x.x.js b/flow-typed/@react-navigation/bottom-tabs_v5.x.x.js
index a2804d8d8ee..0bf92f2365a 100644
--- a/flow-typed/@react-navigation/bottom-tabs_v5.x.x.js
+++ b/flow-typed/@react-navigation/bottom-tabs_v5.x.x.js
@@ -26,7 +26,7 @@ declare module '@react-navigation/bottom-tabs' {
     | false
     | ''
     | $ReadOnlyArray<StyleObj>
-    | { [name: string]: any, ... };
+    | {| [name: string]: any |};
   declare type ViewStyleProp = StyleObj;
   declare type TextStyleProp = StyleObj;
   declare type AnimatedViewStyleProp = StyleObj;
@@ -425,7 +425,7 @@ declare module '@react-navigation/bottom-tabs' {
    * Actions, state, etc.
    */
 
-  declare export type ScreenParams = { +[key: string]: mixed, ... };
+  declare export type ScreenParams = {| +[key: string]: mixed |};
 
   declare export type BackAction = {|
     +type: 'GO_BACK',
@@ -474,7 +474,7 @@ declare module '@react-navigation/bottom-tabs' {
 
   declare export type GenericNavigationAction = {|
     +type: string,
-    +payload?: { +[key: string]: mixed, ... },
+    +payload?: {| +[key: string]: mixed |},
     +source?: string,
     +target?: string,
   |};
@@ -540,10 +540,9 @@ declare module '@react-navigation/bottom-tabs' {
   declare type ActionCreators<
     State: NavigationState,
     Action: GenericNavigationAction,
-  > = {
+  > = {|
     +[key: string]: (...args: any) => (Action | State => Action),
-    ...
-  };
+  |};
 
   declare export type DefaultRouterOptions = {
     +initialRouteName?: string,
@@ -556,7 +555,7 @@ declare module '@react-navigation/bottom-tabs' {
     RouterOptions: DefaultRouterOptions,
   > = (options: RouterOptions) => Router<State, Action>;
 
-  declare export type ParamListBase = { +[key: string]: ?ScreenParams, ... };
+  declare export type ParamListBase = {| +[key: string]: ?ScreenParams |};
 
   declare export type RouterConfigOptions = {|
     +routeNames: $ReadOnlyArray<string>,
@@ -714,13 +713,12 @@ declare module '@react-navigation/bottom-tabs' {
    * Events
    */
 
-  declare export type EventMapBase = {
+  declare export type EventMapBase = {|
     +[name: string]: {|
       +data?: mixed,
       +canPreventDefault?: boolean,
     |},
-    ...
-  };
+  |};
   declare type EventPreventDefaultProperties<Test: boolean> = $If<
     Test,
     {| +defaultPrevented: boolean, +preventDefault: () => void |},
@@ -1910,7 +1908,7 @@ declare module '@react-navigation/bottom-tabs' {
   declare export type ContainerEventMap = {|
     ...GlobalEventMap<PossiblyStaleNavigationState>,
     +options: {|
-      +data: {| +options: { +[key: string]: mixed, ... } |},
+      +data: {| +options: {| +[key: string]: mixed |} |},
       +canPreventDefault: false,
     |},
     +__unsafe_action__: {|
diff --git a/flow-typed/@react-navigation/drawer_v5.x.x.js b/flow-typed/@react-navigation/drawer_v5.x.x.js
index b2cf468edd1..fa861bcf09e 100644
--- a/flow-typed/@react-navigation/drawer_v5.x.x.js
+++ b/flow-typed/@react-navigation/drawer_v5.x.x.js
@@ -26,7 +26,7 @@ declare module '@react-navigation/drawer' {
     | false
     | ''
     | $ReadOnlyArray<StyleObj>
-    | { [name: string]: any, ... };
+    | {| [name: string]: any |};
   declare type ViewStyleProp = StyleObj;
   declare type TextStyleProp = StyleObj;
   declare type AnimatedViewStyleProp = StyleObj;
@@ -425,7 +425,7 @@ declare module '@react-navigation/drawer' {
    * Actions, state, etc.
    */
 
-  declare export type ScreenParams = { +[key: string]: mixed, ... };
+  declare export type ScreenParams = {| +[key: string]: mixed |};
 
   declare export type BackAction = {|
     +type: 'GO_BACK',
@@ -474,7 +474,7 @@ declare module '@react-navigation/drawer' {
 
   declare export type GenericNavigationAction = {|
     +type: string,
-    +payload?: { +[key: string]: mixed, ... },
+    +payload?: {| +[key: string]: mixed |},
     +source?: string,
     +target?: string,
   |};
@@ -540,10 +540,9 @@ declare module '@react-navigation/drawer' {
   declare type ActionCreators<
     State: NavigationState,
     Action: GenericNavigationAction,
-  > = {
+  > = {|
     +[key: string]: (...args: any) => (Action | State => Action),
-    ...
-  };
+  |};
 
   declare export type DefaultRouterOptions = {
     +initialRouteName?: string,
@@ -556,7 +555,7 @@ declare module '@react-navigation/drawer' {
     RouterOptions: DefaultRouterOptions,
   > = (options: RouterOptions) => Router<State, Action>;
 
-  declare export type ParamListBase = { +[key: string]: ?ScreenParams, ... };
+  declare export type ParamListBase = {| +[key: string]: ?ScreenParams |};
 
   declare export type RouterConfigOptions = {|
     +routeNames: $ReadOnlyArray<string>,
@@ -714,13 +713,12 @@ declare module '@react-navigation/drawer' {
    * Events
    */
 
-  declare export type EventMapBase = {
+  declare export type EventMapBase = {|
     +[name: string]: {|
       +data?: mixed,
       +canPreventDefault?: boolean,
     |},
-    ...
-  };
+  |};
   declare type EventPreventDefaultProperties<Test: boolean> = $If<
     Test,
     {| +defaultPrevented: boolean, +preventDefault: () => void |},
@@ -1910,7 +1908,7 @@ declare module '@react-navigation/drawer' {
   declare export type ContainerEventMap = {|
     ...GlobalEventMap<PossiblyStaleNavigationState>,
     +options: {|
-      +data: {| +options: { +[key: string]: mixed, ... } |},
+      +data: {| +options: {| +[key: string]: mixed |} |},
       +canPreventDefault: false,
     |},
     +__unsafe_action__: {|
diff --git a/flow-typed/@react-navigation/material-top-tabs_v5.x.x.js b/flow-typed/@react-navigation/material-top-tabs_v5.x.x.js
index 300781d34e4..9f33f0eab5e 100644
--- a/flow-typed/@react-navigation/material-top-tabs_v5.x.x.js
+++ b/flow-typed/@react-navigation/material-top-tabs_v5.x.x.js
@@ -26,7 +26,7 @@ declare module '@react-navigation/material-top-tabs' {
     | false
     | ''
     | $ReadOnlyArray<StyleObj>
-    | { [name: string]: any, ... };
+    | {| [name: string]: any |};
   declare type ViewStyleProp = StyleObj;
   declare type TextStyleProp = StyleObj;
   declare type AnimatedViewStyleProp = StyleObj;
@@ -425,7 +425,7 @@ declare module '@react-navigation/material-top-tabs' {
    * Actions, state, etc.
    */
 
-  declare export type ScreenParams = { +[key: string]: mixed, ... };
+  declare export type ScreenParams = {| +[key: string]: mixed |};
 
   declare export type BackAction = {|
     +type: 'GO_BACK',
@@ -474,7 +474,7 @@ declare module '@react-navigation/material-top-tabs' {
 
   declare export type GenericNavigationAction = {|
     +type: string,
-    +payload?: { +[key: string]: mixed, ... },
+    +payload?: {| +[key: string]: mixed |},
     +source?: string,
     +target?: string,
   |};
@@ -540,10 +540,9 @@ declare module '@react-navigation/material-top-tabs' {
   declare type ActionCreators<
     State: NavigationState,
     Action: GenericNavigationAction,
-  > = {
+  > = {|
     +[key: string]: (...args: any) => (Action | State => Action),
-    ...
-  };
+  |};
 
   declare export type DefaultRouterOptions = {
     +initialRouteName?: string,
@@ -556,7 +555,7 @@ declare module '@react-navigation/material-top-tabs' {
     RouterOptions: DefaultRouterOptions,
   > = (options: RouterOptions) => Router<State, Action>;
 
-  declare export type ParamListBase = { +[key: string]: ?ScreenParams, ... };
+  declare export type ParamListBase = {| +[key: string]: ?ScreenParams |};
 
   declare export type RouterConfigOptions = {|
     +routeNames: $ReadOnlyArray<string>,
@@ -714,13 +713,12 @@ declare module '@react-navigation/material-top-tabs' {
    * Events
    */
 
-  declare export type EventMapBase = {
+  declare export type EventMapBase = {|
     +[name: string]: {|
       +data?: mixed,
       +canPreventDefault?: boolean,
     |},
-    ...
-  };
+  |};
   declare type EventPreventDefaultProperties<Test: boolean> = $If<
     Test,
     {| +defaultPrevented: boolean, +preventDefault: () => void |},
@@ -1910,7 +1908,7 @@ declare module '@react-navigation/material-top-tabs' {
   declare export type ContainerEventMap = {|
     ...GlobalEventMap<PossiblyStaleNavigationState>,
     +options: {|
-      +data: {| +options: { +[key: string]: mixed, ... } |},
+      +data: {| +options: {| +[key: string]: mixed |} |},
       +canPreventDefault: false,
     |},
     +__unsafe_action__: {|
diff --git a/flow-typed/@react-navigation/native_v5.x.x.js b/flow-typed/@react-navigation/native_v5.x.x.js
index f23b9b922cd..ae0d0fdb15f 100644
--- a/flow-typed/@react-navigation/native_v5.x.x.js
+++ b/flow-typed/@react-navigation/native_v5.x.x.js
@@ -26,7 +26,7 @@ declare module '@react-navigation/native' {
     | false
     | ''
     | $ReadOnlyArray<StyleObj>
-    | { [name: string]: any, ... };
+    | {| [name: string]: any |};
   declare type ViewStyleProp = StyleObj;
   declare type TextStyleProp = StyleObj;
   declare type AnimatedViewStyleProp = StyleObj;
@@ -425,7 +425,7 @@ declare module '@react-navigation/native' {
    * Actions, state, etc.
    */
 
-  declare export type ScreenParams = { +[key: string]: mixed, ... };
+  declare export type ScreenParams = {| +[key: string]: mixed |};
 
   declare export type BackAction = {|
     +type: 'GO_BACK',
@@ -474,7 +474,7 @@ declare module '@react-navigation/native' {
 
   declare export type GenericNavigationAction = {|
     +type: string,
-    +payload?: { +[key: string]: mixed, ... },
+    +payload?: {| +[key: string]: mixed |},
     +source?: string,
     +target?: string,
   |};
@@ -540,10 +540,9 @@ declare module '@react-navigation/native' {
   declare type ActionCreators<
     State: NavigationState,
     Action: GenericNavigationAction,
-  > = {
+  > = {|
     +[key: string]: (...args: any) => (Action | State => Action),
-    ...
-  };
+  |};
 
   declare export type DefaultRouterOptions = {
     +initialRouteName?: string,
@@ -556,7 +555,7 @@ declare module '@react-navigation/native' {
     RouterOptions: DefaultRouterOptions,
   > = (options: RouterOptions) => Router<State, Action>;
 
-  declare export type ParamListBase = { +[key: string]: ?ScreenParams, ... };
+  declare export type ParamListBase = {| +[key: string]: ?ScreenParams |};
 
   declare export type RouterConfigOptions = {|
     +routeNames: $ReadOnlyArray<string>,
@@ -714,13 +713,12 @@ declare module '@react-navigation/native' {
    * Events
    */
 
-  declare export type EventMapBase = {
+  declare export type EventMapBase = {|
     +[name: string]: {|
       +data?: mixed,
       +canPreventDefault?: boolean,
     |},
-    ...
-  };
+  |};
   declare type EventPreventDefaultProperties<Test: boolean> = $If<
     Test,
     {| +defaultPrevented: boolean, +preventDefault: () => void |},
@@ -1910,7 +1908,7 @@ declare module '@react-navigation/native' {
   declare export type ContainerEventMap = {|
     ...GlobalEventMap<PossiblyStaleNavigationState>,
     +options: {|
-      +data: {| +options: { +[key: string]: mixed, ... } |},
+      +data: {| +options: {| +[key: string]: mixed |} |},
       +canPreventDefault: false,
     |},
     +__unsafe_action__: {|
diff --git a/flow-typed/@react-navigation/stack_v5.x.x.js b/flow-typed/@react-navigation/stack_v5.x.x.js
index 9e82f8e04ec..958d817e2ac 100644
--- a/flow-typed/@react-navigation/stack_v5.x.x.js
+++ b/flow-typed/@react-navigation/stack_v5.x.x.js
@@ -26,7 +26,7 @@ declare module '@react-navigation/stack' {
     | false
     | ''
     | $ReadOnlyArray<StyleObj>
-    | { [name: string]: any, ... };
+    | {| [name: string]: any |};
   declare type ViewStyleProp = StyleObj;
   declare type TextStyleProp = StyleObj;
   declare type AnimatedViewStyleProp = StyleObj;
@@ -425,7 +425,7 @@ declare module '@react-navigation/stack' {
    * Actions, state, etc.
    */
 
-  declare export type ScreenParams = { +[key: string]: mixed, ... };
+  declare export type ScreenParams = {| +[key: string]: mixed |};
 
   declare export type BackAction = {|
     +type: 'GO_BACK',
@@ -474,7 +474,7 @@ declare module '@react-navigation/stack' {
 
   declare export type GenericNavigationAction = {|
     +type: string,
-    +payload?: { +[key: string]: mixed, ... },
+    +payload?: {| +[key: string]: mixed |},
     +source?: string,
     +target?: string,
   |};
@@ -540,10 +540,9 @@ declare module '@react-navigation/stack' {
   declare type ActionCreators<
     State: NavigationState,
     Action: GenericNavigationAction,
-  > = {
+  > = {|
     +[key: string]: (...args: any) => (Action | State => Action),
-    ...
-  };
+  |};
 
   declare export type DefaultRouterOptions = {
     +initialRouteName?: string,
@@ -556,7 +555,7 @@ declare module '@react-navigation/stack' {
     RouterOptions: DefaultRouterOptions,
   > = (options: RouterOptions) => Router<State, Action>;
 
-  declare export type ParamListBase = { +[key: string]: ?ScreenParams, ... };
+  declare export type ParamListBase = {| +[key: string]: ?ScreenParams |};
 
   declare export type RouterConfigOptions = {|
     +routeNames: $ReadOnlyArray<string>,
@@ -714,13 +713,12 @@ declare module '@react-navigation/stack' {
    * Events
    */
 
-  declare export type EventMapBase = {
+  declare export type EventMapBase = {|
     +[name: string]: {|
       +data?: mixed,
       +canPreventDefault?: boolean,
     |},
-    ...
-  };
+  |};
   declare type EventPreventDefaultProperties<Test: boolean> = $If<
     Test,
     {| +defaultPrevented: boolean, +preventDefault: () => void |},
@@ -1910,7 +1908,7 @@ declare module '@react-navigation/stack' {
   declare export type ContainerEventMap = {|
     ...GlobalEventMap<PossiblyStaleNavigationState>,
     +options: {|
-      +data: {| +options: { +[key: string]: mixed, ... } |},
+      +data: {| +options: {| +[key: string]: mixed |} |},
       +canPreventDefault: false,
     |},
     +__unsafe_action__: {|
diff --git a/flow-typed/@sentry/react-native_v2.x.x.js b/flow-typed/@sentry/react-native_v2.x.x.js
index 6a6d88d38c8..646cd814607 100644
--- a/flow-typed/@sentry/react-native_v2.x.x.js
+++ b/flow-typed/@sentry/react-native_v2.x.x.js
@@ -1,5 +1,4 @@
 declare module '@sentry/react-native' {
-
   declare type Primitive =
     | number
     | string
@@ -57,7 +56,7 @@ declare module '@sentry/react-native' {
     event_id?: string,
     message?: string,
     timestamp?: number,
-    start_timestamp?: number;
+    start_timestamp?: number,
     level?: SeverityType,
     platform?: string,
     logger?: string,
@@ -68,14 +67,14 @@ declare module '@sentry/react-native' {
     // sdk?: SdkInfo,
     // request?: Request,
     transaction?: string,
-    modules?: { [key: string]: string },
+    modules?: {| [key: string]: string |},
     fingerprint?: string[],
     // exception?: { values?: Exception[], },
     // stacktrace?: Stacktrace,
     breadcrumbs?: Breadcrumb[],
-    // contexts?: { [key: string]: object },
-    tags?: { [key: string]: Primitive },
-    extra?: { [key: string]: any },
+    // contexts?: {| [key: string]: object |},
+    tags?: {| [key: string]: Primitive |},
+    extra?: {| [key: string]: any |},
     // user?: User,
     type?: EventType,
   |};
@@ -86,7 +85,7 @@ declare module '@sentry/react-native' {
   // Taken from @sentry/types/src/event.ts.
   declare export type EventHint = {|
     event_id?: string,
-    captureContext?: CaptureContext;
+    captureContext?: CaptureContext,
     syntheticException?: Error | null,
     originalException?: Error | string | null,
     data?: mixed,
@@ -99,9 +98,9 @@ declare module '@sentry/react-native' {
     event_id?: string,
     category?: string,
     message?: string,
-    data?: {
-      [key: string]: mixed;
-  },
+    data?: {|
+      [key: string]: mixed,
+    |},
     timestamp?: number,
   |};
 
@@ -120,9 +119,9 @@ declare module '@sentry/react-native' {
      * Set an object that will be merged sent as tags data with the event.
      * @param tags Tags context object to merge into current context.
      */
-    setTags(tags: {
+    setTags(tags: {|
       +[key: string]: Primitive,
-    }): this;
+    |}): this;
     /**
      * Set key:value that will be sent as tags data with the event.
      * @param key String key of tag
@@ -140,7 +139,7 @@ declare module '@sentry/react-native' {
      * Set an object that will be merged sent as extra data with the event.
      * @param extras Extras object to merge into current context.
      */
-    setExtras(extras: { +[key: string]: any }): this;
+    setExtras(extras: {| +[key: string]: any |}): this;
   }
 
   declare export type CaptureContext = Scope | Partial<ScopeContext> | ((scope: Scope) => Scope);
@@ -160,8 +159,14 @@ declare module '@sentry/react-native' {
   // https://docs.sentry.io/development/sdk-dev/unified-api/#static-api
   //
   // Taken from @sentry/minimal/src/index.ts.
-  declare export function captureException(exception: mixed, captureContext?: CaptureContext): string;
-  declare export function captureMessage(message: string, captureContext?: CaptureContext | SeverityType): string;
+  declare export function captureException(
+    exception: mixed,
+    captureContext?: CaptureContext,
+  ): string;
+  declare export function captureMessage(
+    message: string,
+    captureContext?: CaptureContext | SeverityType,
+  ): string;
   declare export function addBreadcrumb(breadcrumb: Breadcrumb): void;
 
   /* Modifies the current scope. Avoid in favor of `withScope` wherever
diff --git a/flow-typed/jest_v26.x.x.js b/flow-typed/jest_v26.x.x.js
index 20876ccf00b..cd4f54928d0 100644
--- a/flow-typed/jest_v26.x.x.js
+++ b/flow-typed/jest_v26.x.x.js
@@ -239,8 +239,8 @@ type DomTestingLibraryType = {
   toHaveAttribute(attr: string, value?: any): void,
   toHaveClass(...classNames: string[]): void,
   toHaveFocus(): void,
-  toHaveFormValues(expectedValues: { [name: string]: any, ... }): void,
-  toHaveStyle(css: string | { [name: string]: any, ... }): void,
+  toHaveFormValues(expectedValues: {| [name: string]: any |}): void,
+  toHaveStyle(css: string | {| [name: string]: any |}): void,
   toHaveTextContent(text: string | RegExp, options?: {| normalizeWhitespace: boolean |}): void,
   toHaveValue(value?: string | string[] | number): void,
 
@@ -262,7 +262,7 @@ type JestJQueryMatchersType = {
   toHaveText(text: string | RegExp): void,
   toHaveData(key: string, val?: any): void,
   toHaveValue(val: any): void,
-  toHaveCss(css: { [key: string]: any, ... }): void,
+  toHaveCss(css: {| [key: string]: any |}): void,
   toBeChecked(): void,
   toBeDisabled(): void,
   toBeEmpty(): void,
@@ -1141,7 +1141,7 @@ declare var expect: {
     JestExtendedMatchersType &
     SnapshotDiffType,
   /** Add additional Jasmine matchers to Jest's roster */
-  extend(matchers: { [name: string]: JestMatcher, ... }): void,
+  extend(matchers: {| [name: string]: JestMatcher |}): void,
   /** Add a module that formats application-specific data structures. */
   addSnapshotSerializer(pluginModule: JestPrettyFormatPlugin): void,
   assertions(expectedAssertions: number): void,
@@ -1184,7 +1184,7 @@ declare var jasmine: {
   createSpyObj(
     baseName: string,
     methodNames: Array<string>,
-  ): { [methodName: string]: JestSpyType, ... },
+  ): {| [methodName: string]: JestSpyType |},
   objectContaining(value: Object): Object,
   stringMatching(value: string): string,
   ...
diff --git a/flow-typed/react-intl_vx.x.x.js b/flow-typed/react-intl_vx.x.x.js
index 4e2c9909149..6ed1c6d7e22 100644
--- a/flow-typed/react-intl_vx.x.x.js
+++ b/flow-typed/react-intl_vx.x.x.js
@@ -36,7 +36,7 @@ declare module 'react-intl' {
     format?: string;
   }
   declare export type CustomFormats = {
-    relative?: { [key: string]: IntlRelativeTimeFormatOptions, ... },
+    relative?: {| [key: string]: IntlRelativeTimeFormatOptions |},
     ...
   } & $Rest<Formats, { ... }>;
   declare type DateElement = SimpleFormatElement<typeof TYPE.date, DateTimeSkeleton>;
@@ -45,8 +45,7 @@ declare module 'react-intl' {
     dateStyle?: 'full' | 'long' | 'medium' | 'short',
     timeStyle?: 'full' | 'long' | 'medium' | 'short',
     fractionalSecondDigits?: number,
-    calendar?:
-      | 'buddhist'
+    calendar?: | 'buddhist'
       | 'chinese'
       | 'coptic'
       | 'ethiopia'
@@ -75,10 +74,9 @@ declare module 'react-intl' {
     | 'textComponent'
     | 'defaultLocale'
     | 'defaultFormats'
-    | 'onError',
-  >;
+    | 'onError', >;
   declare export function defineMessage<T>(msg: T): T;
-  declare export function defineMessages<K: $Keys<any>, T, U: { [key: K]: T, ... }>(msgs: U): U;
+  declare export function defineMessages<K: $Keys<any>, T, U: {| [key: K]: T |}>(msgs: U): U;
   declare class DisplayNames {
     constructor(locales?: string | string[], options?: DisplayNamesOptions): this;
     static supportedLocalesOf(
@@ -86,9 +84,9 @@ declare module 'react-intl' {
       options?: Pick<DisplayNamesOptions, 'localeMatcher'>,
     ): string[];
     static __addLocaleData(...data: DisplayNamesLocaleData[]): void;
-    of(code: string | number | { [key: string]: any }): string | void;
+    of(code: string | number | {| [key: string]: any |}): string | void;
     resolvedOptions(): DisplayNamesResolvedOptions;
-    static localeData: { [key: string]: DisplayNamesData, ... };
+    static localeData: {| [key: string]: DisplayNamesData |};
     static +polyfilled: any; // true
   }
   declare interface DisplayNamesData {
@@ -101,27 +99,27 @@ declare module 'react-intl' {
        * Maps language subtag like `zh-CN` to their display names.
        */
       language: {
-        narrow: { [key: LanguageTag]: string, ... },
-        short: { [key: LanguageTag]: string, ... },
-        long: { [key: LanguageTag]: string, ... },
+        narrow: {| [key: LanguageTag]: string |},
+        short: {| [key: LanguageTag]: string |},
+        long: {| [key: LanguageTag]: string |},
         ...
       },
       region: {
-        narrow: { [key: RegionCode]: string, ... },
-        short: { [key: RegionCode]: string, ... },
-        long: { [key: RegionCode]: string, ... },
+        narrow: {| [key: RegionCode]: string |},
+        short: {| [key: RegionCode]: string |},
+        long: {| [key: RegionCode]: string |},
         ...
       },
       script: {
-        narrow: { [key: ScriptCode]: string, ... },
-        short: { [key: ScriptCode]: string, ... },
-        long: { [key: ScriptCode]: string, ... },
+        narrow: {| [key: ScriptCode]: string |},
+        short: {| [key: ScriptCode]: string |},
+        long: {| [key: ScriptCode]: string |},
         ...
       },
       currency: {
-        narrow: { [key: CurrencyCode]: string, ... },
-        short: { [key: CurrencyCode]: string, ... },
-        long: { [key: CurrencyCode]: string, ... },
+        narrow: {| [key: CurrencyCode]: string |},
+        short: {| [key: CurrencyCode]: string |},
+        long: {| [key: CurrencyCode]: string |},
         ...
       },
       ...
@@ -200,13 +198,12 @@ declare module 'react-intl' {
     CustomFormatConfig;
   declare export type FormatRelativeTimeOptions = Exclude<
     IntlRelativeTimeFormatOptions,
-    'localeMatcher',
-  > &
+    'localeMatcher', > &
     CustomFormatConfig;
   declare interface Formats {
-    number: { [key: string]: Intl.NumberFormatOptions, ... };
-    date: { [key: string]: Intl.DateTimeFormatOptions, ... };
-    time: { [key: string]: Intl.DateTimeFormatOptions, ... };
+    number: {| [key: string]: Intl.NumberFormatOptions |};
+    date: {| [key: string]: Intl.DateTimeFormatOptions |};
+    time: {| [key: string]: Intl.DateTimeFormatOptions |};
   }
   declare type FormattableUnit = Unit | Units;
   declare export var FormattedDate: React$StatelessFunctionalComponent<
@@ -214,35 +211,30 @@ declare module 'react-intl' {
       CustomFormatConfig & {
         value: string | number | Date | void,
         ...
-      },
-  >;
+      }, >;
   declare export var FormattedDateParts: React$StatelessFunctionalComponent<
     FormatDateOptions & {
       value: $ElementType<Parameters<$PropertyType<Intl.DateTimeFormat, 'format'>>, 0> | string,
       children(val: Intl.DateTimeFormatPart[]): React_2.ReactElement<> | null,
       ...
-    },
-  >;
+    }, >;
   declare export var FormattedDisplayName: React$StatelessFunctionalComponent<
     DisplayNamesOptions & {
-      value: string | number | { [key: string]: any },
+      value: string | number | {| [key: string]: any |},
       ...
-    },
-  >;
+    }, >;
   declare export var FormattedList: React$StatelessFunctionalComponent<
     IntlListFormatOptions & {
       value: React$Node[],
       ...
-    },
-  >;
+    }, >;
   declare export class FormattedMessage<
-    V: { [key: string]: any, ... } = {
+    V: {| [key: string]: any |} = {|
       [key: string]:
         | PrimitiveType
         | React_2.ReactElement<>
         | FormatXMLElementFn<React$Node, React$Node>,
-      ...,
-    },
+    |},
     // Changed `mixins` to `extends` in TS to Flow translation
   > extends React$Component<Props_3<V>> {
     static displayName: string;
@@ -254,15 +246,13 @@ declare module 'react-intl' {
       CustomFormatConfig & {
         value: number,
         ...
-      },
-  >;
+      }, >;
   declare export var FormattedNumberParts: React$StatelessFunctionalComponent<
     $PropertyType<Formatter, 'formatNumber'> & {
       value: $ElementType<Parameters<$PropertyType<IntlShape, 'formatNumber'>>, 0>,
       children(val: Intl.NumberFormatPart[]): React_2.ReactElement<> | null,
       ...
-    },
-  >;
+    }, >;
   declare export var FormattedPlural: React$StatelessFunctionalComponent<WithIntlProps<Props_2>> & {
     WrappedComponent: React$ComponentType<Props_2>,
     ...
@@ -286,15 +276,13 @@ declare module 'react-intl' {
       CustomFormatConfig & {
         value: string | number | Date | void,
         ...
-      },
-  >;
+      }, >;
   declare export var FormattedTimeParts: React$StatelessFunctionalComponent<
     FormatDateOptions & {
       value: $ElementType<Parameters<$PropertyType<Intl.DateTimeFormat, 'format'>>, 0> | string,
       children(val: Intl.DateTimeFormatPart[]): React_2.ReactElement<> | null,
       ...
-    },
-  >;
+    }, >;
   declare type Formatter = {
     formatDate: FormatDateOptions,
     formatTime: FormatDateOptions,
@@ -341,32 +329,30 @@ declare module 'react-intl' {
     WrappedComponent: React$ComponentType<P>,
     options?: Opts<IntlPropName, true>,
   ): React_2.ForwardRefExoticComponent<
-    React_2.PropsWithoutRef<WithIntlProps<React_2.PropsWithChildren<P>>> & React_2.RefAttributes<T>,
-  > & {
+    React_2.PropsWithoutRef<WithIntlProps<React_2.PropsWithChildren<P>>> & React_2.RefAttributes<T>, > & {
     WrappedComponent: React$ComponentType<P>,
     ...
   };
   declare export interface IntlCache {
-    dateTime: { [key: string]: Intl.DateTimeFormat, ... };
-    number: { [key: string]: Intl.NumberFormat, ... };
-    message: { [key: string]: IntlMessageFormat, ... };
-    relativeTime: { [key: string]: RelativeTimeFormat, ... };
-    pluralRules: { [key: string]: Intl.PluralRules, ... };
-    list: { [key: string]: ListFormat, ... };
-    displayNames: { [key: string]: DisplayNames, ... };
+    dateTime: {| [key: string]: Intl.DateTimeFormat |};
+    number: {| [key: string]: Intl.NumberFormat |};
+    message: {| [key: string]: IntlMessageFormat |};
+    relativeTime: {| [key: string]: RelativeTimeFormat |};
+    pluralRules: {| [key: string]: Intl.PluralRules |};
+    list: {| [key: string]: ListFormat |};
+    displayNames: {| [key: string]: DisplayNames |};
   }
   declare export interface IntlConfig {
     locale: string;
     timeZone?: string;
     formats: CustomFormats;
     textComponent?: React$ComponentType<> | $Keys<React_2.ReactHTML>;
-    messages: { [key: string]: string, ... } | { [key: string]: MessageFormatElement[], ... };
+    messages: {| [key: string]: string |} | {| [key: string]: MessageFormatElement[] |};
     defaultLocale: string;
     defaultFormats: CustomFormats;
     wrapRichTextChunksInFragment?: boolean;
     onError(
-      err:
-        | MissingTranslationError
+      err: | MissingTranslationError
         | MessageFormatError
         | MissingDataError
         | InvalidConfigError
@@ -413,13 +399,13 @@ declare module 'react-intl' {
       descriptor: MessageDescriptor,
       // The `+` was added to make the properties covariant rather
       // than invariant, something TypeScript can't do.
-      values?: { +[key: string]: PrimitiveType | FormatXMLElementFn<string, string>, ... },
+      values?: {| +[key: string]: PrimitiveType | FormatXMLElementFn<string, string> |},
     ): string;
     formatMessage(
       descriptor: MessageDescriptor,
       // The `+` was added to make the properties covariant rather
       // than invariant, something TypeScript can't do.
-      values?: { +[key: string]: PrimitiveType | React$Node | FormatXMLElementFn<T, R>, ... },
+      values?: {| +[key: string]: PrimitiveType | React$Node | FormatXMLElementFn<T, R> |},
     ): React$Node;
     formatList(values: Array<string>, opts?: FormatListOptions): string;
     formatList(values: Array<string | React$Node>, opts?: FormatListOptions): React$Node;
@@ -463,9 +449,8 @@ declare module 'react-intl' {
       opts?: Options,
     ): this;
     format: <T>(
-      values?: {
-        [key: string]:
-          | string
+      values?: {|
+        [key: string]: | string
           | number
           | boolean
           | Date
@@ -473,13 +458,11 @@ declare module 'react-intl' {
           | FormatXMLElementFn<T, string | (string | T)[]>
           | null
           | void,
-        ...,
-      } | void,
+      |} | void,
     ) => string | T | (string | T)[];
     formatToParts: <T>(
-      values?: {
-        [key: string]:
-          | string
+      values?: {|
+        [key: string]: | string
           | number
           | boolean
           | Date
@@ -487,8 +470,7 @@ declare module 'react-intl' {
           | FormatXMLElementFn<T, string | (string | T)[]>
           | null
           | void,
-        ...,
-      } | void,
+      |} | void,
     ) => MessageFormatPart<T>[];
     resolvedOptions: () => {
       locale: string,
@@ -568,9 +550,11 @@ declare module 'react-intl' {
       ...
     };
   }
-  declare export class IntlProvider
+  declare export class IntlProvider extends React$PureComponent<
     // Changed `mixins` to `extends` in TS to Flow translation
-    extends React$PureComponent<React_2.PropsWithChildren<OptionalIntlConfig>, State> {
+    React_2.PropsWithChildren<OptionalIntlConfig>,
+    State,
+  > {
     static displayName: string;
     static defaultProps: Pick<
       IntlConfig,
@@ -580,8 +564,7 @@ declare module 'react-intl' {
       | 'messages'
       | 'textComponent'
       | 'defaultLocale'
-      | 'defaultFormats',
-    >;
+      | 'defaultFormats', >;
     state: State;
     static getDerivedStateFromProps(
       props: OptionalIntlConfig,
@@ -643,7 +626,7 @@ declare module 'react-intl' {
       options?: Pick<IntlListFormatOptions, 'localeMatcher'>,
     ): string[];
     static __addLocaleData(...data: ListPatternLocaleData[]): void;
-    static localeData: { [key: string]: ListPatternFieldsData, ... };
+    static localeData: {| [key: string]: ListPatternFieldsData |};
     static polyfilled: boolean;
   }
   declare interface ListPattern {
@@ -674,10 +657,12 @@ declare module 'react-intl' {
   }
   declare type Locale = string;
   declare interface LocaleData<T> {
-    data: { [key: Locale]: T, ... };
+    data: {| [key: Locale]: T |};
     availableLocales: string[];
   }
-  declare type LocaleFieldsData = $ObjMapi<{ [k: RelativeTimeField]: any }, <f>(f) => FieldData> & {
+  declare type LocaleFieldsData = $ObjMapi<
+    {| [k: RelativeTimeField]: any |},
+    <f>(f) => FieldData, > & {
     nu?: Array<string | null>,
     ...
   };
@@ -693,7 +678,7 @@ declare module 'react-intl' {
   // Changed from interface to type in TS to Flow translation
   declare export type MessageDescriptor = {
     id?: string | number,
-    description?: string | { [key: string]: any },
+    description?: string | {| [key: string]: any |},
     defaultMessage?: string,
   };
   declare type MessageFormatElement =
@@ -819,7 +804,7 @@ declare module 'react-intl' {
     +object: 1, // 1
   |};
   declare type PluralElement = {
-    options: { [key: ValidPluralRule]: PluralOrSelectOption, ... },
+    options: {| [key: ValidPluralRule]: PluralOrSelectOption |},
     offset: number,
     pluralType: $PropertyType<Intl.PluralRulesOptions, 'type'>,
     ...
@@ -852,7 +837,7 @@ declare module 'react-intl' {
     children?: (value: React$Node) => React_2.ReactElement<> | null,
     ...
   } & FormatPluralOptions;
-  declare type Props_3<V: { [key: string]: any, ... } = { [key: string]: React$Node, ... }> = {
+  declare type Props_3<V: {| [key: string]: any |} = {| [key: string]: React$Node |}> = {
     values?: V,
     tagName?: React_2.ElementType<any>,
     children?: (...nodes: React_2.ReactNodeArray) => React$Node,
@@ -873,7 +858,7 @@ declare module 'react-intl' {
     +MISSING_TRANSLATION: 'MISSING_TRANSLATION', // "MISSING_TRANSLATION"
   |};
   declare type RegionCode = string;
-  declare type RelativeTimeData = $ObjMapi<{ [k: LDMLPluralRule]: any }, <u>(u) => string>;
+  declare type RelativeTimeData = $ObjMapi<{| [k: LDMLPluralRule]: any |}, <u>(u) => string>;
   declare type RelativeTimeField =
     | 'second'
     | 'second-short'
@@ -909,7 +894,7 @@ declare module 'react-intl' {
       options?: Pick<IntlRelativeTimeFormatOptions, 'localeMatcher'>,
     ): string[];
     static __addLocaleData(...data: RelativeTimeLocaleData[]): void;
-    static localeData: { [key: string]: LocaleFieldsData, ... };
+    static localeData: {| [key: string]: LocaleFieldsData |};
     static polyfilled: boolean;
   }
   declare type RelativeTimeFormatNumberPart = {
@@ -964,7 +949,7 @@ declare module 'react-intl' {
   };
   declare type ScriptCode = string;
   declare type SelectElement = {
-    options: { [key: string]: PluralOrSelectOption, ... },
+    options: {| [key: string]: PluralOrSelectOption |},
     ...
   } & BaseElement<typeof TYPE.select>;
   declare type SimpleFormatElement<T: $Values<typeof TYPE>, S: Skeleton> = {
@@ -1040,8 +1025,7 @@ declare module 'react-intl' {
     ...
   };
   declare export type WrappedComponentProps<IntlPropName: string = 'intl'> = $ObjMapi<
-    { [k: IntlPropName]: any },
-    <k>(k) => IntlShape,
-  >;
+    {| [k: IntlPropName]: any |},
+    <k>(k) => IntlShape, >;
   declare export {};
 }
diff --git a/flow-typed/react-native-url-polyfill_vx.x.x.js b/flow-typed/react-native-url-polyfill_vx.x.x.js
index 75bd7d22dbb..be250ce390d 100644
--- a/flow-typed/react-native-url-polyfill_vx.x.x.js
+++ b/flow-typed/react-native-url-polyfill_vx.x.x.js
@@ -28,7 +28,7 @@ declare module 'react-native-url-polyfill/js/URLSearchParams' {
   declare export class URLSearchParams {
     @@iterator(): Iterator<[string, string]>;
     constructor(
-      query?: string | URLSearchParams | Array<[string, string]> | { [string]: string },
+      query?: string | URLSearchParams | Array<[string, string]> | {| [string]: string |},
     ): void;
     append(name: string, value: string): void;
     delete(name: string): void;
diff --git a/flow-typed/react-native-webview_v10.x.x.js b/flow-typed/react-native-webview_v10.x.x.js
index 3bdafafc3a8..43f42813059 100644
--- a/flow-typed/react-native-webview_v10.x.x.js
+++ b/flow-typed/react-native-webview_v10.x.x.js
@@ -138,7 +138,7 @@ declare module 'react-native-webview' {
   declare export type WebViewSourceUri = {|
     uri?: string,
     method?: string,
-    headers?: { [string]: string },
+    headers?: {| [string]: string |},
     body?: string,
   |};
 
diff --git a/package.json b/package.json
index 0cd97f207b5..fad5a8105b9 100644
--- a/package.json
+++ b/package.json
@@ -116,7 +116,7 @@
     "eslint-plugin-prettier": "^3.2.0",
     "eslint-plugin-react": "^7.21.5",
     "eslint-plugin-react-hooks": "^4.2.0",
-    "flow-bin": "^0.122.0",
+    "flow-bin": "^0.128.0",
     "flow-coverage-report": "^0.6.0",
     "flow-typed": "^2.4.0",
     "immutable-devtools": "^0.1.5",
diff --git a/src/__tests__/lib/exampleData.js b/src/__tests__/lib/exampleData.js
index 7782ac1fa29..2b9c1384059 100644
--- a/src/__tests__/lib/exampleData.js
+++ b/src/__tests__/lib/exampleData.js
@@ -330,9 +330,9 @@ export const pmMessage = (args?: {|
   // The `Object.freeze` is to work around a Flow issue:
   //   https://github.com/facebook/flow/issues/2386#issuecomment-695064325
   const {
-    sender = otherUser,
-    recipients = [otherUser, selfUser],
     sender_id = undefined,
+    sender = sender_id != null ? makeUser({ user_id: sender_id }) : otherUser,
+    recipients = [otherUser, selfUser],
     ...extra
   } = args ?? Object.freeze({});
 
@@ -355,7 +355,6 @@ export const pmMessage = (args?: {|
 
   return deepFreeze({
     ...baseMessage,
-    ...(sender_id != null && { sender_id: makeUserId(sender_id) }),
     ...extra,
   });
 };
@@ -674,7 +673,7 @@ export const action = deepFreeze({
 // annotate `action` itself, because we want to keep the information of
 // which one has which specific type.)
 /* eslint-disable-next-line no-unused-expressions */
-(action: { [string]: Action });
+(action: {| [string]: Action |});
 
 /* ========================================================================
  * Action fragments
diff --git a/src/api/initialDataTypes.js b/src/api/initialDataTypes.js
index 62686e294c7..af32e0c9f34 100644
--- a/src/api/initialDataTypes.js
+++ b/src/api/initialDataTypes.js
@@ -38,9 +38,9 @@ export type InitialDataPresence = {|
   presences: {| [email: string]: UserPresence |},
 |};
 
-export type AvailableVideoChatProviders = {
+export type AvailableVideoChatProviders = {|
   [providerName: string]: {| name: string, id: number |},
-};
+|};
 
 export type InitialDataRealm = {|
   jitsi_server_url?: string,
@@ -171,7 +171,7 @@ export type InitialDataSubscription = {|
 export type InitialDataUpdateDisplaySettings = {|
   default_language: string,
   emojiset: string,
-  emojiset_choices: { [string]: string },
+  emojiset_choices: {| [string]: string |},
   high_contrast_mode: boolean,
   left_side_userlist: boolean,
   night_mode: boolean,
diff --git a/src/api/modelTypes.js b/src/api/modelTypes.js
index b3cd66efc65..3d14bddd8e3 100644
--- a/src/api/modelTypes.js
+++ b/src/api/modelTypes.js
@@ -30,9 +30,9 @@ export type ImageEmojiType = $ReadOnly<{|
   source_url: string,
 |}>;
 
-export type RealmEmojiById = $ReadOnly<{
+export type RealmEmojiById = $ReadOnly<{|
   [id: string]: ImageEmojiType,
-}>;
+|}>;
 
 export type RealmFilter = [string, string, number];
 
@@ -462,7 +462,7 @@ export type Submessage = $ReadOnly<{|
  *    `EVENT_NEW_MESSAGE` Redux action for the event;
  *  * `messages: Message[]` in a `/messages` (our `getMessages`) response,
  *    and our resulting `MESSAGE_FETCH_COMPLETE` Redux action;
- *  * `messages: { [id]: Message }` in our global Redux state.
+ *  * `messages: {| [id]: Message |}` in our global Redux state.
  *
  * References include:
  *  * the two example events at https://zulip.com/api/get-events-from-queue
diff --git a/src/autocomplete/PeopleAutocomplete.js b/src/autocomplete/PeopleAutocomplete.js
index e5652db02a5..0e387d54992 100644
--- a/src/autocomplete/PeopleAutocomplete.js
+++ b/src/autocomplete/PeopleAutocomplete.js
@@ -87,16 +87,18 @@ class PeopleAutocomplete extends PureComponent<Props> {
 
     return (
       <Popup>
-        {/*
-          $FlowFixMe[incompatible-variance]
-          $FlowFixMe[prop-missing]
-          SectionList type is confused; should take $ReadOnly objects.
-        */}
-        <SectionList
-          keyboardShouldPersistTaps="always"
-          initialNumToRender={10}
-          sections={sections}
-        />
+        {/* eslint-disable-next-line react/jsx-curly-brace-presence */}
+        {
+          // $FlowFixMe[incompatible-variance]
+          /* $FlowFixMe[prop-missing]
+             SectionList type is confused; should take $ReadOnly
+             objects. */
+          <SectionList
+            keyboardShouldPersistTaps="always"
+            initialNumToRender={10}
+            sections={sections}
+          />
+        }
       </Popup>
     );
   }
diff --git a/src/boot/store.js b/src/boot/store.js
index 55aaba8060e..c1f538d2941 100644
--- a/src/boot/store.js
+++ b/src/boot/store.js
@@ -90,8 +90,13 @@ export const cacheKeys: Array<$Keys<GlobalState>> = [
 function dropCache(state: GlobalState): $Shape<GlobalState> {
   const result: $Shape<GlobalState> = {};
   storeKeys.forEach(key => {
-    /* $FlowFixMe[incompatible-type]: This is well-typed only because
-       it's the same `key` twice. */
+    // $FlowFixMe[incompatible-indexer]
+    // $FlowFixMe[incompatible-exact]
+    // $FlowFixMe[prop-missing]
+    // $FlowFixMe[incompatible-variance]
+    // $FlowFixMe[incompatible-type-arg]
+    /* $FlowFixMe[incompatible-type]
+       This is well-typed only because it's the same `key` twice. */
     result[key] = state[key];
   });
   return result;
@@ -106,7 +111,7 @@ function dropCache(state: GlobalState): $Shape<GlobalState> {
  * a version number to track which migrations are already reflected in it,
  * so that each only has to be run once.
  */
-const migrations: { [string]: (GlobalState) => GlobalState } = {
+const migrations: {| [string]: (GlobalState) => GlobalState |} = {
   // The type is a lie, in several ways:
   //  * The actual object contains only the properties we persist:
   //    those in `storeKeys` and `cacheKeys`, but not `discardKeys`.
@@ -168,8 +173,8 @@ const migrations: { [string]: (GlobalState) => GlobalState } = {
     ...state,
     accounts: state.accounts.map(a => ({
       ...a,
-      // `a.realm` is a string until migration 15
-      // $FlowMigrationFudge[prop-missing]
+      /* $FlowIgnore[prop-missing]: `a.realm` is a string until
+         migration 15 */
       realm: a.realm.replace(/\/+$/, ''),
     })),
   }),
@@ -206,8 +211,8 @@ const migrations: { [string]: (GlobalState) => GlobalState } = {
     ...state,
     accounts: state.accounts.map(a => ({
       ...a,
-      /* $FlowMigrationFudge[incompatible-call]: `a.realm` will be a
-         string here */
+      /* $FlowIgnore[incompatible-call]: `a.realm` will be a string
+         here */
       realm: new URL(a.realm),
     })),
   }),
diff --git a/src/compose/ComposeMenu.js b/src/compose/ComposeMenu.js
index 964129ec333..11a4119ec3a 100644
--- a/src/compose/ComposeMenu.js
+++ b/src/compose/ComposeMenu.js
@@ -83,7 +83,9 @@ class ComposeMenu extends PureComponent<Props> {
       return;
     }
 
-    // $FlowFixMe[sketchy-null-bool]: Upstream API is unclear.
+    // $FlowFixMe[sketchy-null-string]
+    /* $FlowFixMe[sketchy-null-bool]
+       Upstream API is unclear. */
     const error: string | null = response.error || null;
     if (error !== null) {
       showErrorAlert('Error', error);
diff --git a/src/directSelectors.js b/src/directSelectors.js
index 16d720f288c..c1e39f13f35 100644
--- a/src/directSelectors.js
+++ b/src/directSelectors.js
@@ -63,7 +63,7 @@ export const getFetching = (state: GlobalState): FetchingState => state.fetching
 
 export const getFlags = (state: GlobalState): FlagsState => state.flags;
 
-export const getReadFlags = (state: GlobalState): { [messageId: number]: boolean } =>
+export const getReadFlags = (state: GlobalState): {| [messageId: number]: boolean |} =>
   state.flags.read;
 
 export const getAllNarrows = (state: GlobalState): NarrowsState => state.narrows;
diff --git a/src/emoji/codePointMap.js b/src/emoji/codePointMap.js
index 622bdc6638c..9fae7e72bd3 100644
--- a/src/emoji/codePointMap.js
+++ b/src/emoji/codePointMap.js
@@ -1,7 +1,7 @@
 /* @flow strict-local */
 
 /** Maps certain emoji to substitutes, for us to show instead. */
-export const override: { [code: string]: string } = {
+export const override: {| [code: string]: string |} = {
   // :check_mark: -> :check: because the former is invisible on a light
   // background, i.e. when not in night mode.
   '2714': '2705',
@@ -19,7 +19,7 @@ export const override: { [code: string]: string } = {
  * Reaction.emoji_code here:
  *   https://github.com/zulip/zulip/blob/master/zerver/models.py
  */
-export const unicodeCodeByName: { [name: string]: string } = {
+export const unicodeCodeByName: {| [name: string]: string |} = {
   '+1': '1f44d',
   '-1': '1f44e',
   '0': '0030-20e3',
diff --git a/src/emoji/data.js b/src/emoji/data.js
index 4df6665383e..d5c0fb4c4c2 100644
--- a/src/emoji/data.js
+++ b/src/emoji/data.js
@@ -35,7 +35,7 @@ export const codeToEmojiMap = objectFromEntries<string, string>(
  */
 export const getFilteredEmojis = (
   query: string,
-  activeImageEmojiByName: $ReadOnly<{ [string]: ImageEmojiType }>,
+  activeImageEmojiByName: $ReadOnly<{| [string]: ImageEmojiType |}>,
 ): $ReadOnlyArray<{| emoji_type: EmojiType, name: string, code: string |}> => {
   // We start by making a map from matching emoji names to a number
   // representing how good a match it is: 0 for a prefix match, 1 for a
diff --git a/src/emoji/emojiSelectors.js b/src/emoji/emojiSelectors.js
index 06cedbcab92..341c39bcec9 100644
--- a/src/emoji/emojiSelectors.js
+++ b/src/emoji/emojiSelectors.js
@@ -10,7 +10,7 @@ export const getAllImageEmojiById: Selector<RealmEmojiById> = createSelector(
   getIdentity,
   getRawRealmEmoji,
   (identity, realmEmoji) => {
-    const result: { [string]: ImageEmojiType } = {};
+    const result: {| [string]: ImageEmojiType |} = {};
     [realmEmoji, zulipExtraEmojiMap].forEach(emojis => {
       Object.keys(emojis).forEach(id => {
         result[id] = {
@@ -26,7 +26,7 @@ export const getAllImageEmojiById: Selector<RealmEmojiById> = createSelector(
 export const getActiveImageEmojiById: Selector<RealmEmojiById> = createSelector(
   getAllImageEmojiById,
   emojis => {
-    const result: { [string]: ImageEmojiType } = {};
+    const result: {| [string]: ImageEmojiType |} = {};
     Object.keys(emojis).forEach(id => {
       if (!emojis[id].deactivated) {
         result[id] = emojis[id];
@@ -36,12 +36,12 @@ export const getActiveImageEmojiById: Selector<RealmEmojiById> = createSelector(
   },
 );
 
-export const getAllImageEmojiByCode: Selector<{ [string]: ImageEmojiType }> = createSelector(
+export const getAllImageEmojiByCode: Selector<{| [string]: ImageEmojiType |}> = createSelector(
   getAllImageEmojiById,
   emojis => objectFromEntries(Object.keys(emojis).map(id => [emojis[id].code, emojis[id]])),
 );
 
-export const getActiveImageEmojiByName: Selector<{ [string]: ImageEmojiType }> = createSelector(
+export const getActiveImageEmojiByName: Selector<{| [string]: ImageEmojiType |}> = createSelector(
   getActiveImageEmojiById,
   emojis => objectFromEntries(Object.keys(emojis).map(id => [emojis[id].name, emojis[id]])),
 );
diff --git a/src/emoji/zulipExtraEmojiMap.js b/src/emoji/zulipExtraEmojiMap.js
index 662bb8fb2a8..e387faf3025 100644
--- a/src/emoji/zulipExtraEmojiMap.js
+++ b/src/emoji/zulipExtraEmojiMap.js
@@ -6,7 +6,7 @@ import type { ImageEmojiType } from '../types';
  * so that both emoji type can be handled in similiar way
  * thus id has no meaning here
  */
-const zulipExtraEmojiMap: { [id: string]: ImageEmojiType } = {
+const zulipExtraEmojiMap: {| [id: string]: ImageEmojiType |} = {
   zulip: {
     deactivated: false,
     code: 'zulip',
diff --git a/src/jsBackport.js b/src/jsBackport.js
index 36fa2140587..c7d87ad20dc 100644
--- a/src/jsBackport.js
+++ b/src/jsBackport.js
@@ -18,8 +18,8 @@
  * implement and is all we happened to need.  Would be nice to extend to
  * iterables.
  */
-export function objectFromEntries<+K, +V>(entries: $ReadOnlyArray<[K, V]>): { [K]: V } {
-  const obj = ({}: { [K]: V });
+export function objectFromEntries<+K, +V>(entries: $ReadOnlyArray<[K, V]>): {| [K]: V |} {
+  const obj = ({}: {| [K]: V |});
   entries.forEach(entry => {
     // ESLint bug?  I don't understand how this rule even applies to this line.
     // eslint-disable-next-line prefer-destructuring
diff --git a/src/message/messageActionSheet.js b/src/message/messageActionSheet.js
index 8df6f9f25b0..620cc7074c6 100644
--- a/src/message/messageActionSheet.js
+++ b/src/message/messageActionSheet.js
@@ -237,7 +237,7 @@ const allButtonsRaw = {
 
 type ButtonCode = $Keys<typeof allButtonsRaw>;
 
-const allButtons: { [ButtonCode]: ButtonDescription } = allButtonsRaw;
+const allButtons: {| [ButtonCode]: ButtonDescription |} = allButtonsRaw;
 
 type ConstructSheetParams<MsgType: Message | Outbox = Message | Outbox> = {|
   backgroundData: BackgroundData,
diff --git a/src/pm-conversations/pmConversationsSelectors.js b/src/pm-conversations/pmConversationsSelectors.js
index d2c10c65021..f537a5fc3c1 100644
--- a/src/pm-conversations/pmConversationsSelectors.js
+++ b/src/pm-conversations/pmConversationsSelectors.js
@@ -38,8 +38,8 @@ export const getRecentConversationsLegacy: Selector<PmConversationData[]> = crea
   (
     ownUserId,
     messages: Message[],
-    unreadPms: { [number]: number },
-    unreadHuddles: { [string]: number },
+    unreadPms: {| [number]: number |},
+    unreadHuddles: {| [string]: number |},
     allUsersById,
   ): PmConversationData[] => {
     const items = messages
diff --git a/src/presence/presenceReducer.js b/src/presence/presenceReducer.js
index a100d7f529b..7f03edadc3c 100644
--- a/src/presence/presenceReducer.js
+++ b/src/presence/presenceReducer.js
@@ -41,17 +41,17 @@ export default (state: PresenceState = initialState, action: Action): PresenceSt
 
       return {
         ...state,
+        // Flow bug (unresolved):
+        // https://github.com/facebook/flow/issues/8276
+        // $FlowIssue #8276
         [action.email]: {
           ...state[action.email],
+          ...action.presence,
           // Flow bug (unresolved):
           // https://github.com/facebook/flow/issues/8276
           // $FlowIssue #8276
-          ...action.presence,
           aggregated: getAggregatedPresence({
             ...state[action.email],
-            // Flow bug (unresolved):
-            // https://github.com/facebook/flow/issues/8276
-            // $FlowIssue #8276
             ...action.presence,
           }),
         },
diff --git a/src/redux-persist-migrate/index.js b/src/redux-persist-migrate/index.js
index 0bf56744fbe..25dcb183aed 100644
--- a/src/redux-persist-migrate/index.js
+++ b/src/redux-persist-migrate/index.js
@@ -16,7 +16,7 @@ const processKey = key => {
 /* eslint-disable no-use-before-define */
 
 export default function createMigration(
-  manifest: { [string]: (State) => State },
+  manifest: {| [string]: (State) => State |},
   versionSelector: string | (State => number | string | void),
   versionSetter?: (State, number) => State,
 ): StoreEnhancer<State, Action, Dispatch<Action>> {
@@ -46,7 +46,7 @@ export default function createMigration(
 }
 
 export function createMigrationImpl(
-  manifest: { [string]: (State) => State },
+  manifest: {| [string]: (State) => State |},
   versionSelector: State => number | string | void,
   versionSetter: (State, number) => State,
 ): StoreEnhancer<State, Action, Dispatch<Action>> {
@@ -75,8 +75,10 @@ export function createMigrationImpl(
       throw new Error('createMigration: bad arguments');
     }
     if (action.type === REHYDRATE) {
-      /* $FlowMigrationFudge[incompatible-type]: this really is a lie
-         -- and kind of central to migration */
+      // $FlowIgnore[prop-missing]
+      // $FlowIgnore[incompatible-exact]
+      /* $FlowIgnore[incompatible-type]
+         this really is a lie -- and kind of central to migration */
       const incomingState: State = action.payload;
       const incomingVersion = parseInt(versionSelector(incomingState), 10);
       if (Number.isNaN(incomingVersion)) {
diff --git a/src/reduxTypes.js b/src/reduxTypes.js
index ad36c7e3944..92d8a79dd61 100644
--- a/src/reduxTypes.js
+++ b/src/reduxTypes.js
@@ -73,20 +73,18 @@ export type CaughtUp = {|
  *
  * See `CaughtUp` for details on what each value means.
  */
-export type CaughtUpState = {
-  // TODO(flow-v0.126): Should be exact. See note in src/utils/jsonable.js.
+export type CaughtUpState = {|
   [narrow: string]: CaughtUp,
-};
+|};
 
 /**
  * The user's draft message, if any, in each conversation.
  *
  * The keys correspond to the keys in `NarrowsState`.
  */
-export type DraftsState = {
-  // TODO(flow-v0.126): Should be exact. See note in src/utils/jsonable.js.
+export type DraftsState = {|
   [narrow: string]: string,
-};
+|};
 
 export type Fetching = {|
   older: boolean,
@@ -100,10 +98,9 @@ export type Fetching = {|
  *
  * See also: `CaughtUpState`, `NarrowsState`.
  */
-export type FetchingState = {
-  // TODO(flow-v0.126): Should be exact. See note in src/utils/jsonable.js.
+export type FetchingState = {|
   [narrow: string]: Fetching,
-};
+|};
 
 /**
  * The message flags corresponding to all the messages in `MessagesState`.
@@ -112,18 +109,18 @@ export type FetchingState = {
  * incomplete, always in exactly the same way that `MessagesState` is.
  */
 export type FlagsState = {|
-  read: { [messageId: number]: boolean },
-  starred: { [messageId: number]: boolean },
-  collapsed: { [messageId: number]: boolean },
-  mentioned: { [messageId: number]: boolean },
-  wildcard_mentioned: { [messageId: number]: boolean },
-  summarize_in_home: { [messageId: number]: boolean },
-  summarize_in_stream: { [messageId: number]: boolean },
-  force_expand: { [messageId: number]: boolean },
-  force_collapse: { [messageId: number]: boolean },
-  has_alert_word: { [messageId: number]: boolean },
-  historical: { [messageId: number]: boolean },
-  is_me_message: { [messageId: number]: boolean },
+  read: {| [messageId: number]: boolean |},
+  starred: {| [messageId: number]: boolean |},
+  collapsed: {| [messageId: number]: boolean |},
+  mentioned: {| [messageId: number]: boolean |},
+  wildcard_mentioned: {| [messageId: number]: boolean |},
+  summarize_in_home: {| [messageId: number]: boolean |},
+  summarize_in_stream: {| [messageId: number]: boolean |},
+  force_expand: {| [messageId: number]: boolean |},
+  force_collapse: {| [messageId: number]: boolean |},
+  has_alert_word: {| [messageId: number]: boolean |},
+  historical: {| [messageId: number]: boolean |},
+  is_me_message: {| [messageId: number]: boolean |},
 |};
 
 export type FlagName = $Keys<FlagsState>;
@@ -207,9 +204,9 @@ export type OutboxState = Outbox[];
  * @prop (email) - Indexes over all users for which the app has received a
  *   presence status.
  */
-export type PresenceState = {
+export type PresenceState = {|
   [email: string]: UserPresence,
-};
+|};
 
 /**
  * Configuration for a video chat provider, as specified by the server.
@@ -290,12 +287,12 @@ export type TopicsState = {|
   [number]: Topic[],
 |};
 
-export type TypingState = {
+export type TypingState = {|
   [normalizedRecipients: string]: {
     time: number,
     userIds: UserId[],
   },
-};
+|};
 
 export type UserGroupsState = UserGroup[];
 
diff --git a/src/streams/StreamList.js b/src/streams/StreamList.js
index 22fd88054d7..f38083152c3 100644
--- a/src/streams/StreamList.js
+++ b/src/streams/StreamList.js
@@ -21,7 +21,7 @@ type Props = $ReadOnly<{|
   showDescriptions: boolean,
   showSwitch: boolean,
   streams: $ReadOnlyArray<PseudoSubscription>,
-  unreadByStream: $ReadOnly<{ [number]: number }>,
+  unreadByStream: $ReadOnly<{| [number]: number |}>,
   onPress: (streamName: string) => void,
   onSwitch?: (streamName: string, newValue: boolean) => void,
 |}>;
diff --git a/src/streams/SubscriptionsCard.js b/src/streams/SubscriptionsCard.js
index 810b62c8de1..23daf1b50b8 100644
--- a/src/streams/SubscriptionsCard.js
+++ b/src/streams/SubscriptionsCard.js
@@ -24,7 +24,7 @@ const styles = createStyleSheet({
 
 type SelectorProps = $ReadOnly<{|
   subscriptions: Subscription[],
-  unreadByStream: $ReadOnly<{ [number]: number }>,
+  unreadByStream: $ReadOnly<{| [number]: number |}>,
 |}>;
 
 type Props = $ReadOnly<{|
diff --git a/src/styles/theme.js b/src/styles/theme.js
index 261454b2512..68c4e3c1e1a 100644
--- a/src/styles/theme.js
+++ b/src/styles/theme.js
@@ -11,7 +11,7 @@ export type ThemeData = {|
   dividerColor: string,
 |};
 
-export const themeData: { [name: ThemeName | 'light']: ThemeData } = {
+export const themeData: {| [name: ThemeName | 'light']: ThemeData |} = {
   night: {
     color: 'hsl(210, 11%, 85%)',
     backgroundColor: 'hsl(212, 28%, 18%)',
diff --git a/src/types.js b/src/types.js
index 164cb8cc3d4..cb0636aec1b 100644
--- a/src/types.js
+++ b/src/types.js
@@ -236,7 +236,7 @@ export type MessageLike =
   | $ReadOnly<Message>
   | $ReadOnly<{
       // $Shape<T> is unsound, per Flow docs, but $ReadOnly<$Shape<T>> is not
-      ...$Shape<{ [$Keys<Message>]: void }>,
+      ...$Shape<{| [$Keys<Message>]: void |}>,
       sender_id?: UserId, // TODO: Drop this once required in Outbox.
       ...Outbox,
     }>;
@@ -246,7 +246,7 @@ type IntlMessageFormatValue = string | number | boolean | null | void;
 
 export type LocalizableText =
   | string
-  | { text: string, values?: { [string]: IntlMessageFormatValue } };
+  | { text: string, values?: {| [string]: IntlMessageFormatValue |} };
 
 /**
  * Usually called `_`, and invoked like `_('Message')` -> `'Nachricht'`.
@@ -264,7 +264,7 @@ export type LocalizableText =
  * @prop intl - The full react-intl API, for more complex situations.
  */
 export type GetText = {
-  (message: string, values?: { [string]: IntlMessageFormatValue }): string,
+  (message: string, values?: {| [string]: IntlMessageFormatValue |}): string,
   intl: IntlShape,
 };
 
diff --git a/src/unread/UnreadCards.js b/src/unread/UnreadCards.js
index 6be1fb055b4..f42d507a8e7 100644
--- a/src/unread/UnreadCards.js
+++ b/src/unread/UnreadCards.js
@@ -35,8 +35,9 @@ export default function UnreadCards(props: Props) {
   }
 
   return (
-    /* $FlowFixMe[prop-missing]: SectionList libdef seems confused;
-         should take $ReadOnly objects. */
+    // $FlowFixMe[incompatible-type-arg]
+    /* $FlowFixMe[prop-missing]
+       SectionList libdef seems confused; should take $ReadOnly objects. */
     <SectionList
       stickySectionHeadersEnabled
       initialNumToRender={20}
diff --git a/src/unread/unreadSelectors.js b/src/unread/unreadSelectors.js
index 1e524c82864..66569154906 100644
--- a/src/unread/unreadSelectors.js
+++ b/src/unread/unreadSelectors.js
@@ -13,12 +13,12 @@ import { pmUnreadsKeyFromPmKeyIds } from '../utils/recipient';
 import { getUnreadStreams, getUnreadPms, getUnreadHuddles, getUnreadMentions } from './unreadModel';
 
 /** The number of unreads in each stream, excluding muted topics, by stream ID. */
-export const getUnreadByStream: Selector<{ [number]: number }> = createSelector(
+export const getUnreadByStream: Selector<{| [number]: number |}> = createSelector(
   getUnreadStreams,
   getSubscriptionsById,
   getMute,
   (unreadStreams, subscriptionsById, mute) => {
-    const totals = ({}: { [number]: number });
+    const totals = ({}: {| [number]: number |});
     unreadStreams.forEach(stream => {
       if (!totals[stream.stream_id]) {
         totals[stream.stream_id] = 0;
@@ -50,10 +50,10 @@ export const getUnreadStreamTotal: Selector<number> = createSelector(
  *
  * See also `getUnreadByHuddles`, for group PM threads.
  */
-export const getUnreadByPms: Selector<{ [number]: number }> = createSelector(
+export const getUnreadByPms: Selector<{| [number]: number |}> = createSelector(
   getUnreadPms,
   unreadPms => {
-    const totals = ({}: { [number]: number });
+    const totals = ({}: {| [number]: number |});
     unreadPms.forEach(pm => {
       totals[pm.sender_id] = totals[pm.sender_id] || 0 + pm.unread_message_ids.length;
     });
@@ -80,10 +80,10 @@ export const getUnreadPmsTotal: Selector<number> = createSelector(
  *
  * See also `getUnreadByPms`, for 1:1 PM threads.
  */
-export const getUnreadByHuddles: Selector<{ [string]: number }> = createSelector(
+export const getUnreadByHuddles: Selector<{| [string]: number |}> = createSelector(
   getUnreadHuddles,
   unreadHuddles => {
-    const totals = ({}: { [string]: number });
+    const totals = ({}: {| [string]: number |});
     unreadHuddles.forEach(huddle => {
       totals[huddle.user_ids_string] =
         totals[huddle.user_ids_string] || 0 + huddle.unread_message_ids.length;
diff --git a/src/utils/jsonable.js b/src/utils/jsonable.js
index 8676e3fc0b0..c21fda86e28 100644
--- a/src/utils/jsonable.js
+++ b/src/utils/jsonable.js
@@ -17,7 +17,7 @@ export type JSONable =
   | string
   | number
   | boolean
-  | { +[string]: JSONable } // [α]
+  | {| +[string]: JSONable |} // [α]
   | $ReadOnlyArray<JSONable>;
 // [α] This should just be `JSONableDict`, but Flow doesn't handle
 //     mutually-recursive types very well.
@@ -27,24 +27,7 @@ export type JSONable =
  *
  * See documentation of `JSONable` for caveats.
  */
-export type JSONableDict = { +[string]: JSONable };
-// This should really be an exact type, `{| +[string]: JSONable |}`.
-// Unfortunately, it can't yet be.
-//
-// Prior to Flow v0.126.0, exact object types with indexer properties
-// are unusably broken. The following trivial example fails to
-// typecheck:
-//
-//    const val: {| [string]: number |} = { foo: 3 };
-//
-// On the other hand, inexact indexer-property types don't actually have their
-// properties typechecked at their point of use -- that is, the following passes
-// typechecking (even after v0.126.0):
-//
-//    const val: { [string]: number } = { foo: 3, bar: 'baz' };
-//
-// ... which is consistent with the definition of inexact types, if
-// inconvenient.
+export type JSONableDict = {| +[string]: JSONable |};
 
 /**
  * Approximate type of a JSONable value received as input.
@@ -54,7 +37,7 @@ export type JSONableDict = { +[string]: JSONable };
  * by-design soundness hole involving indexer elements:
  *
  * ```flow
- *   const obj: { [string]: string } = { a: "a" };
+ *   const obj: {| [string]: string |} = { a: "a" };
  *   const value: string = obj['b'];
  *   value.trim();  // kaboom!
  * ```
@@ -89,7 +72,7 @@ export type JSONableInput =
   | string
   | number
   | boolean
-  | { +[string]: JSONableInput | void }
+  | {| +[string]: JSONableInput | void |}
   | $ReadOnlyArray<JSONableInput>;
 
 /**
@@ -97,4 +80,4 @@ export type JSONableInput =
  *
  * See documentation of `JSONable` and `JSONableInput` for caveats.
  */
-export type JSONableInputDict = { +[string]: JSONableInput | void };
+export type JSONableInputDict = {| +[string]: JSONableInput | void |};
diff --git a/src/utils/logging.js b/src/utils/logging.js
index 93cf31e46c4..adc188681af 100644
--- a/src/utils/logging.js
+++ b/src/utils/logging.js
@@ -13,9 +13,7 @@ import objectEntries from './objectEntries';
 import config from '../config';
 
 /** Type of "extras" intended for Sentry. */
-// This type should be exact, but cannot be until Flow v0.126.0. (See note in
-// `jsonable.js`.)
-type Extras = { +[key: string]: JSONable };
+type Extras = {| +[key: string]: JSONable |};
 
 /** Wrapper for `Sentry.withScope`, allowing callbacks to return values. */
 function withScope<R>(callback: Scope => R): R {
diff --git a/src/utils/misc.js b/src/utils/misc.js
index 6ecf7fac895..0d944b945e2 100644
--- a/src/utils/misc.js
+++ b/src/utils/misc.js
@@ -8,7 +8,7 @@ export const caseInsensitiveCompareFunc = (a: string, b: string): number =>
 export const numberWithSeparators = (value: number | string): string =>
   value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',');
 
-export function deeperMerge<K, V>(obj1: { [K]: V }, obj2: { [K]: V }): { [K]: V } {
+export function deeperMerge<K, V>(obj1: {| [K]: V |}, obj2: {| [K]: V |}): {| [K]: V |} {
   const mergedKeys = Array.from(new Set([...Object.keys(obj1), ...Object.keys(obj2)]));
   return objectFromEntries(
     mergedKeys.map(key =>
diff --git a/src/utils/objectEntries.js b/src/utils/objectEntries.js
index dbd2e0c9c0a..b8f815475e0 100644
--- a/src/utils/objectEntries.js
+++ b/src/utils/objectEntries.js
@@ -6,26 +6,8 @@
 //    static entries(object: mixed): Array<[string, mixed]>;
 // .... which is almost useless.
 
-type EntriesType = <K: string, V>({ +[K]: V }) => $ReadOnlyArray<[K, V]>;
+type EntriesType = <K: string, V>({| +[K]: V |}) => $ReadOnlyArray<[K, V]>;
 
 const objectEntries: EntriesType = obj => (Object.entries(obj): $FlowFixMe);
 
 export default objectEntries;
-
-/*
- * Note that the above definition is formally unsound. In particular,
- *
- * ```
- *   const obj: { 'foo': string } = { foo: "yes", bar: 2 };
- *   const vals: string[] = entries(obj).map(s => s[1]);
- *   const valsPadded: string[] = vals.map(v => v.padStart(5));
- * ```
- *
- * ... will pass typechecking, but fail at runtime.
- *
- * To make this function sound, it is necessary that the input type be an
- * _exact_ type. However, the primary use case for this function is map-objects
- * declared with indexer properties; and, until Flow v0.126.0, exact types with
- * indexer properties are unusable. (See comments in ./jsonable.js for more
- * information.)
- */
diff --git a/src/utils/timing.js b/src/utils/timing.js
index 0c1c9f44d80..293daa62946 100644
--- a/src/utils/timing.js
+++ b/src/utils/timing.js
@@ -1,7 +1,7 @@
 /* @flow strict-local */
 import type { TimingItemType } from '../types';
 
-const startMsMap: { [string]: number } = {};
+const startMsMap: {| [string]: number |} = {};
 const log: TimingItemType[] = [];
 
 const add = (item: TimingItemType) => {
diff --git a/src/utils/url.js b/src/utils/url.js
index 9ef2f2f1606..a35ca08adcb 100644
--- a/src/utils/url.js
+++ b/src/utils/url.js
@@ -10,7 +10,7 @@ import objectEntries from './objectEntries';
  * primitive types for which `toString` is just as good as `JSON.stringify`.
  */
 export type UrlParamValue = string | boolean | number;
-export type UrlParams = $ReadOnly<{ [string]: UrlParamValue | void }>;
+export type UrlParams = $ReadOnly<{| [string]: UrlParamValue | void |}>;
 
 /**
  * Encode parameters as if for the URL query-part submitting an HTML form.
@@ -108,7 +108,7 @@ const getResourceNoAuth = (uri: string) => ({
 export const getResource = (
   uri: string,
   auth: Auth,
-): {| uri: string, headers?: { [string]: string } |} =>
+): {| uri: string, headers?: {| [string]: string |} |} =>
   isUrlOnRealm(uri, auth.realm) ? getResourceWithAuth(uri, auth) : getResourceNoAuth(uri);
 
 export type Protocol = 'https://' | 'http://';
diff --git a/src/webview/MessageList.js b/src/webview/MessageList.js
index e82ab291f32..e0655a65e12 100644
--- a/src/webview/MessageList.js
+++ b/src/webview/MessageList.js
@@ -72,7 +72,7 @@ import { tryParseUrl } from '../utils/url';
  */
 export type BackgroundData = $ReadOnly<{|
   alertWords: AlertWordsState,
-  allImageEmojiById: $ReadOnly<{ [id: string]: ImageEmojiType }>,
+  allImageEmojiById: $ReadOnly<{| [id: string]: ImageEmojiType |}>,
   auth: Auth,
   debug: Debug,
   flags: FlagsState,
diff --git a/src/webview/html/messageAsHtml.js b/src/webview/html/messageAsHtml.js
index 09de4c8299e..4df03408884 100644
--- a/src/webview/html/messageAsHtml.js
+++ b/src/webview/html/messageAsHtml.js
@@ -32,7 +32,7 @@ const messageTagsAsHtml = (isStarred: boolean, timeEdited: number | void): strin
 
 const messageReactionAsHtml = (
   reaction: AggregatedReaction,
-  allImageEmojiById: $ReadOnly<{ [id: string]: ImageEmojiType }>,
+  allImageEmojiById: $ReadOnly<{| [id: string]: ImageEmojiType |}>,
 ): string =>
   template`<span onClick="" class="reaction${reaction.selfReacted ? ' self-voted' : ''}"
         data-name="${reaction.name}"
@@ -46,7 +46,7 @@ const messageReactionAsHtml = (
 const messageReactionListAsHtml = (
   reactions: $ReadOnlyArray<Reaction>,
   ownUserId: UserId,
-  allImageEmojiById: $ReadOnly<{ [id: string]: ImageEmojiType }>,
+  allImageEmojiById: $ReadOnly<{| [id: string]: ImageEmojiType |}>,
 ): string => {
   if (reactions.length === 0) {
     return '';
diff --git a/src/webview/js/InboundEventLogger.js b/src/webview/js/InboundEventLogger.js
index 41115735f40..8e4e8a74402 100644
--- a/src/webview/js/InboundEventLogger.js
+++ b/src/webview/js/InboundEventLogger.js
@@ -11,8 +11,7 @@ import type { JSONable } from '../../utils/jsonable';
 import sendMessage from './sendMessage';
 import { ensureUnreachable } from '../../types';
 
-// TODO: Make exact (see note in jsonable.js).
-type Scrub<E: WebViewInboundEvent> = { [key: $Keys<E>]: JSONable };
+type Scrub<E: WebViewInboundEvent> = {| [key: $Keys<E>]: JSONable |};
 
 type ScrubbedInboundEvent =
   | Scrub<WebViewInboundEventContent>
diff --git a/src/webview/js/js.js b/src/webview/js/js.js
index 63c3f4ddd63..3e4734d65c7 100644
--- a/src/webview/js/js.js
+++ b/src/webview/js/js.js
@@ -53,10 +53,9 @@ declare var platformOS: string;
 
 /* Polyfill Array.from. Native in Chrome 45 and at least Safari 13.
    Leaves out some of the fancy features (see MDN). */
-type ArrayLike<T> = { [indexer: number]: T, length: number, ... };
 if (!Array.from) {
   // $FlowFixMe[cannot-write] (polyfill)
-  Array.from = function from<T>(arr: ArrayLike<T>): Array<T> {
+  Array.from = function from<T>(arr: $ArrayLike<T>): Array<T> {
     return Array.prototype.slice.call(arr);
   };
 }
@@ -675,6 +674,7 @@ const handleMessageEvent: MessageEventListener = e => {
 
   inboundEvents.forEach((uevent: WebViewInboundEvent) => {
     eventLogger.maybeCaptureInboundEvent(uevent);
+    // $FlowFixMe[incompatible-type]
     // $FlowFixMe[prop-missing]
     inboundEventHandlers[uevent.type](uevent);
   });
diff --git a/yarn.lock b/yarn.lock
index 30964768a50..3b57add3513 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5621,10 +5621,10 @@ flow-annotation-check@1.8.1:
     glob "7.1.1"
     load-pkg "^3.0.1"
 
-flow-bin@^0.122.0:
-  version "0.122.0"
-  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.122.0.tgz#c723a2b33b1a70bd10204704ae1dc776d5d89d79"
-  integrity sha512-my8N5jgl/A+UVby9E7NDppHdhLgRbWgKbmFZSx2MSYMRh3d9YGnM2MM+wexpUpl0ftY1IM6ZcUwaAhrypLyvlA==
+flow-bin@^0.128.0:
+  version "0.128.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.128.0.tgz#fd1232a64dc46874d8d499f16a1934b964f4c2ae"
+  integrity sha512-EnmMSOCrkx8F0r1+T1d1HODQ+ddy5yRfkT3CvwmK05IWZyXQy27OVdNwdXUWRqc0iMW75T4QkoXaVBYrMqfk+A==
 
 flow-coverage-report@^0.6.0:
   version "0.6.2"