cmov+dbl: add new MSRV policy to README.md (#1211)

See RustCrypto/meta#26

Author: tarcieri

cmov/README.md

@@ -49,13 +49,13 @@ this implementation generates branch-free code.
 It's possible to extend constant-time guarantees to other CPU  architectures.
 Please open an issue with your desired CPU architecture if this interests you.
 
-## Minimum Supported Rust Version
+## Minimum Supported Rust Version (MSRV) Policy
 
-Rust **1.85** or newer.
+MSRV increases are not considered breaking changes and can happen in patch
+releases.
 
-In the future, we reserve the right to change MSRV (i.e. MSRV is out-of-scope
-for this crate's SemVer guarantees), however when we do it will be accompanied by
-a minor version bump.
+The crate MSRV accounts for all supported targets and crate feature
+combinations, excluding explicitly unstable features.
 
 ## License
 

dbl/README.md

@@ -11,6 +11,14 @@ Double operation (a.k.a. "multiply-by-x") in Galois Field `GF(2^n)` using
 the lexicographically first polynomial among the irreducible degree `n` polynomials
 having a minimum number of coefficients.
 
+## Minimum Supported Rust Version (MSRV) Policy
+
+MSRV increases are not considered breaking changes and can happen in patch
+releases.
+
+The crate MSRV accounts for all supported targets and crate feature
+combinations, excluding explicitly unstable features.
+
 ## License
 
 Licensed under either of: