Backward compatibility: the key store with drivers
Promise that we will try to keep backward compatibility with basic driver
usage, but not with more experimental aspects.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/BRANCHES.md b/BRANCHES.md
index e08ae87..f6cdd65 100644
--- a/BRANCHES.md
+++ b/BRANCHES.md
@@ -78,6 +78,12 @@
LTS, but future major version upgrades (for example from 2.28.x/3.x to 4.y)
may require the use of an upgrade tool.
+Note that this guarantee does not currently fully extend to drivers, which
+are an experimental feature. We intend to maintain compatibility with the
+basic use of drivers from Mbed TLS 2.28.0 onwards, even if driver APIs
+change. However, for more experimental parts of the driver interface, such
+as the use of driver state, we do not yet guarantee backward compatibility.
+
## Long-time support branches
For the LTS branches, additionally we try very hard to also maintain ABI
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 65260bc..f9642e7 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -1184,8 +1184,9 @@
*
* Requires: MBEDTLS_PSA_CRYPTO_C
*
- * \warning This interface is experimental and may change or be removed
- * without notice.
+ * \warning This interface is experimental. We intend to maintain backward
+ * compatibility with application code that relies on drivers,
+ * but the driver interfaces may change without notice.
*/
//#define MBEDTLS_PSA_CRYPTO_DRIVERS