diff --git a/lib/mixins/property-effects.js b/lib/mixins/property-effects.js
index c7e68cff47..857e786fb9 100644
--- a/lib/mixins/property-effects.js
+++ b/lib/mixins/property-effects.js
@@ -622,7 +622,9 @@ function applyBindingValue(inst, node, binding, part, value) {
           inst._enqueueClient(node);
         }
       }
-    } else  {
+    } else if (!legacyNoBatch || inst.__dataReady)  {
+      // In legacy no-batching mode, bindings applied before dataReady are
+      // equivalent to the "apply config" phase, which only set managed props
       inst._setUnmanagedPropertyToNode(node, prop, value);
     }
   }
@@ -1555,7 +1557,30 @@ export const PropertyEffects = dedupingMixin(superClass => {
      */
     _flushProperties() {
       this.__dataCounter++;
-      super._flushProperties();
+      if (legacyNoBatch && !this.__dataReady) {
+        // The first time this element is being flushed, propagate pending
+        // data down the tree first; this approximates 1.x's distributeConfig
+        this._propagatePropertyChanges(this.__dataPending, {}, false);
+        // Flushing clients causes this element to become __dataReady
+        this._flushClients();
+        // Capture element data and flush properties one-by one to defeat
+        // Polymer 2.x's batched _propertiesChanged scheme; this approximates
+        // 1.x's applyConfig
+        const changedProps = this.__data;
+        const notify = this.__dataToNotify;
+        this.__data = {};
+        this.__dataPending = this.__dataToNotify = null;
+        for (let prop in changedProps) {
+          const value = changedProps[prop];
+          this.__data[prop] = value;
+          this.__dataPending = {[prop]: value};
+          this.__dataOld = {};
+          this.__dataToNotify = {[prop]: notify && notify[prop]};
+          super._flushProperties();
+        }
+      } else {
+        super._flushProperties();
+      }
       this.__dataCounter--;
     }
 
@@ -1698,12 +1723,21 @@ export const PropertyEffects = dedupingMixin(superClass => {
       // ----------------------------
       let hasPaths = this.__dataHasPaths;
       this.__dataHasPaths = false;
+      let notifyProps;
       // Compute properties
-      runComputedEffects(this, changedProps, oldProps, hasPaths);
-      // Clear notify properties prior to possible reentry (propagate, observe),
-      // but after computing effects have a chance to add to them
-      let notifyProps = this.__dataToNotify;
-      this.__dataToNotify = null;
+      if (legacyNoBatch) {
+        // When not batching, computed effects may re-enter, so capture
+        // notifying properties early
+        notifyProps = this.__dataToNotify;
+        this.__dataToNotify = null;
+        runEffects(this, this[TYPES.COMPUTE], changedProps, oldProps, hasPaths);
+      } else {
+        runComputedEffects(this, changedProps, oldProps, hasPaths);
+        // Clear notify properties prior to possible reentry (propagate, observe),
+        // but after computing effects have a chance to add to them
+        notifyProps = this.__dataToNotify;
+        this.__dataToNotify = null;
+      }
       // Propagate properties to clients
       this._propagatePropertyChanges(changedProps, oldProps, hasPaths);
       // Flush clients
diff --git a/test/runner.html b/test/runner.html
index 8f67390d67..341b02899d 100644
--- a/test/runner.html
+++ b/test/runner.html
@@ -31,6 +31,8 @@
       'unit/template-stamp.html',
       'unit/strict-template-policy.html',
       'unit/property-effects.html',
+      'unit/property-effects.html?legacyUndefined=true',
+      'unit/property-effects.html?legacyUndefined=true&legacyNoBatch=true',
       'unit/property-effects-template.html',
       'unit/path-effects.html',
       'unit/shady.html',
diff --git a/test/unit/property-effects-elements.js b/test/unit/property-effects-elements.js
index 7986f2a6f7..0e0f6094d6 100644
--- a/test/unit/property-effects-elements.js
+++ b/test/unit/property-effects-elements.js
@@ -298,7 +298,9 @@ Polymer({
   },
 
   $computeTrickyFunctionFromLiterals: function(num, str) {
-    return this.computeFromLiterals(num, str);
+    assert.equal(num, 3);
+    assert.equal(str, 'foo');
+    return num + str;
   },
 
   computeFromTrickyLiterals: function(a, b) {
diff --git a/test/unit/property-effects.html b/test/unit/property-effects.html
index 087023914f..37b211b85a 100644
--- a/test/unit/property-effects.html
+++ b/test/unit/property-effects.html
@@ -26,9 +26,13 @@
 <script type="module">
 import './property-effects-elements.js';
 import { Polymer, html } from '../../polymer-legacy.js';
-import { setSanitizeDOMValue, sanitizeDOMValue, setLegacyOptimizations } from '../../lib/utils/settings.js';
+import { setSanitizeDOMValue, sanitizeDOMValue, setLegacyOptimizations, legacyUndefined, setLegacyUndefined, legacyNoBatch, setLegacyNoBatch } from '../../lib/utils/settings.js';
 import { PropertyEffects } from '../../lib/mixins/property-effects.js';
 
+setLegacyUndefined(Boolean(window.location.search.match('legacyUndefined'))); 
+setLegacyNoBatch(Boolean(window.location.search.match('legacyNoBatch')));
+
+
 suite('single-element binding effects', function() {
 
   var el;
@@ -1234,7 +1238,9 @@
     el.cpnd3 = {prop: 'cpnd3'};
     assert.equal(el.$.boundProps.prop1, 'cpnd1cpnd2cpnd3');
     el.cpnd4 = 'cpnd4';
-    assert.equal(el.$.boundProps.prop1, 'cpnd1cpnd2cpnd3literalComputedcpnd4');
+    assert.equal(el.$.boundProps.prop1, 
+      legacyUndefined ?
+      'cpnd1cpnd2cpnd3' : 'cpnd1cpnd2cpnd3literalComputedcpnd4');
     el.cpnd5 = 'cpnd5';
     assert.equal(el.$.boundProps.prop1, 'cpnd1cpnd2cpnd3literalComputedcpnd5cpnd4');
   });
@@ -1265,7 +1271,9 @@
     el.cpnd3 = {prop: 'cpnd3'};
     assert.equal(el.$.boundChild.getAttribute('compoundAttr1'), 'cpnd1cpnd2cpnd3');
     el.cpnd4 = 'cpnd4';
-    assert.equal(el.$.boundChild.getAttribute('compoundAttr1'), 'cpnd1cpnd2cpnd3literalComputedcpnd4');
+    assert.equal(el.$.boundChild.getAttribute('compoundAttr1'), 
+      legacyUndefined ?
+      'cpnd1cpnd2cpnd3' : 'cpnd1cpnd2cpnd3literalComputedcpnd4');
     el.cpnd5 = 'cpnd5';
     assert.equal(el.$.boundChild.getAttribute('compoundAttr1'), 'cpnd1cpnd2cpnd3literalComputedcpnd5cpnd4');
   });
@@ -1302,7 +1310,9 @@
     el.cpnd3 = {prop: 'cpnd3'};
     assert.equal(el.$.compound1.textContent, 'cpnd1cpnd2cpnd3');
     el.cpnd4 = 'cpnd4';
-    assert.equal(el.$.compound1.textContent, 'cpnd1cpnd2cpnd3literalComputedcpnd4');
+    assert.equal(el.$.compound1.textContent, 
+      legacyUndefined ?
+      'cpnd1cpnd2cpnd3' : 'cpnd1cpnd2cpnd3literalComputedcpnd4');
     el.cpnd5 = 'cpnd5';
     assert.equal(el.$.compound1.textContent, 'cpnd1cpnd2cpnd3literalComputedcpnd5cpnd4');
     // Once the binding evaluates back to '', it will in fact be ''
@@ -1770,29 +1780,57 @@
     customElements.define('pe-method-observer', TestClass);
     let el = document.createElement('pe-method-observer');
     document.body.appendChild(el);
-    assert.equal(el.observer.callCount, 1);
-    assert.deepEqual(el.observer.getCall(0).args, [undefined, undefined]);
+    if (legacyUndefined) {
+      assert.equal(el.observer.callCount, 0);
+    } else {
+      assert.equal(el.observer.callCount, 1);
+      assert.deepEqual(el.observer.getCall(0).args, [undefined, undefined]);
+    }
     assert.equal(el.pcSpy.callCount, 1);
     el.a = 'a';
-    assert.equal(el.observer.callCount, 2);
-    assert.deepEqual(el.observer.getCall(1).args, ['a', undefined]);
+    if (legacyUndefined) {
+      assert.equal(el.observer.callCount, 0);
+    } else {
+      assert.equal(el.observer.callCount, 2);
+      assert.deepEqual(el.observer.getCall(1).args, ['a', undefined]);
+    }
     assert.equal(el.pcSpy.callCount, 2);
     el.b = {c: 'c'};
-    assert.equal(el.observer.callCount, 3);
-    assert.deepEqual(el.observer.getCall(2).args, ['a', 'c']);
+    if (legacyUndefined) {
+      assert.equal(el.observer.callCount, 1);
+      assert.deepEqual(el.observer.getCall(0).args, ['a', 'c']);
+    } else {
+      assert.equal(el.observer.callCount, 3);
+      assert.deepEqual(el.observer.getCall(2).args, ['a', 'c']);
+    }
     assert.equal(el.pcSpy.callCount, 3);
     el.setProperties({
       a: 'A',
       b: {c: 'C'}
     });
-    assert.equal(el.observer.callCount, 4);
-    assert.deepEqual(el.observer.getCall(3).args, ['A', 'C']);
-    assert.equal(el.pcSpy.callCount, 4);
+    if (legacyNoBatch && legacyUndefined) {
+      assert.equal(el.observer.callCount, 3);
+      assert.deepEqual(el.observer.getCall(1).args, ['A', 'c']);
+      assert.deepEqual(el.observer.getCall(2).args, ['A', 'C']);
+      assert.equal(el.pcSpy.callCount, 5);
+    } else if (legacyUndefined) {
+      assert.equal(el.observer.callCount, 2);
+      assert.deepEqual(el.observer.getCall(1).args, ['A', 'C']);
+      assert.equal(el.pcSpy.callCount, 4);
+    } else {
+      assert.equal(el.observer.callCount, 4);
+      assert.deepEqual(el.observer.getCall(3).args, ['A', 'C']);
+      assert.equal(el.pcSpy.callCount, 4);
+    }
 
     el.observer = sinon.spy();
     assert.equal(el.observer.callCount, 1);
     assert.deepEqual(el.observer.getCall(0).args, ['A', 'C']);
-    assert.equal(el.pcSpy.callCount, 5);
+    if (legacyNoBatch && legacyUndefined) {
+      assert.equal(el.pcSpy.callCount, 6);
+    } else {
+      assert.equal(el.pcSpy.callCount, 5);
+    }
     document.body.removeChild(el);
   });
 
@@ -1810,23 +1848,43 @@
     assert.equal(el.compute.callCount, 0);
     assert.equal(el.pcSpy.callCount, 0);
     el.a = 'a';
-    assert.equal(el.compute.callCount, 1);
-    assert.deepEqual(el.compute.getCall(0).args, ['a', undefined]);
-    assert.equal(el.prop, 'aundefined');
+    if (legacyUndefined) {
+      assert.equal(el.compute.callCount, 0);
+    } else {
+      assert.equal(el.compute.callCount, 1);
+      assert.deepEqual(el.compute.getCall(0).args, ['a', undefined]);
+      assert.equal(el.prop, 'aundefined');
+    }
     assert.equal(el.pcSpy.callCount, 1);
     el.b = {c: 'c'};
-    assert.equal(el.compute.callCount, 2);
-    assert.deepEqual(el.compute.getCall(1).args, ['a', 'c']);
+    if (legacyUndefined) {
+      assert.equal(el.compute.callCount, 1);
+      assert.deepEqual(el.compute.getCall(0).args, ['a', 'c']);
+    } else {
+      assert.equal(el.compute.callCount, 2);
+      assert.deepEqual(el.compute.getCall(1).args, ['a', 'c']);
+    }
     assert.equal(el.prop, 'ac');
     assert.equal(el.pcSpy.callCount, 2);
     el.setProperties({
       a: 'A',
       b: {c: 'C'}
     });
-    assert.equal(el.compute.callCount, 3);
-    assert.deepEqual(el.compute.getCall(2).args, ['A', 'C']);
+    if (legacyNoBatch && legacyUndefined) {
+      assert.equal(el.compute.callCount, 3);
+      assert.deepEqual(el.compute.getCall(1).args, ['A', 'c']);
+      assert.deepEqual(el.compute.getCall(2).args, ['A', 'C']);
+      assert.equal(el.pcSpy.callCount, 4);
+    } else if (legacyUndefined) {
+      assert.equal(el.compute.callCount, 2);
+      assert.deepEqual(el.compute.getCall(1).args, ['A', 'C']);
+      assert.equal(el.pcSpy.callCount, 3);
+    } else {
+      assert.equal(el.compute.callCount, 3);
+      assert.deepEqual(el.compute.getCall(2).args, ['A', 'C']);
+      assert.equal(el.pcSpy.callCount, 3);
+    }
     assert.equal(el.prop, 'AC');
-    assert.equal(el.pcSpy.callCount, 3);
     document.body.removeChild(el);
   });