Update version to 9.1.0-rc2 and add release notes

00-RELEASENOTES

@@ -11,6 +11,38 @@ Upgrade urgency levels:
 | CRITICAL | There is a critical bug affecting MOST USERS. Upgrade ASAP.         |
 | SECURITY | There are security fixes in the release.                            |
 
+Valkey 9.1.0-rc2 - Released Thu Apr 17 00:00:00 2026
+-------------------------------------
+
+Upgrade urgency LOW: This is the second release candidate of Valkey 9.1.0.
+
+### New Features and enhanced behavior
+* Do the failover immediately if the replica is the best ranked replica by @enjoy-binbin (#2227)
+* Add `cluster-config-save-behavior` option to control nodes.conf save behavior by @enjoy-binbin (#3372)
+* Adds new (hidden) `ValkeyModule_CallArgv` API functions by @rjd15372 (#3122)
+
+### Performance and Efficiency improvements
+* Redesign IO threading communication model with lock-free queues (8-17% throughput gain) by @akashkgit (#3324)
+* Increase embedded string threshold from 64 to 128 bytes (30% GET throughput gain) by @Nikhil-Manglore (#3397)
+* ARM NEON SIMD optimization for pvFind() in vset.c (2-3x speedup) by @ahmadbelb (#3033)
+* Optimize WATCH duplicate key check from O(N) to O(1) using per-db hashtable by @enjoy-binbin (#3360)
+* CLUSTERSCAN MATCH pattern maps to a specific slot optimizations by @nmvk (#3380)
+* Defer argument redaction by storing indices instead of rewriting argv by @rjd15372 (#3471)
+
+### Bug Fixes
+* Fix `valkey-cli --cluster del-node` for unreachable nodes by @yang-z-o (#3209)
+* Enhance cluster stale packet detection to prevent sub-replica and empty primary by @zhijun42 (#2811)
+* Handle EAGAIN in clusterWriteHandler by @enjoy-binbin (#3421)
+* Big endian bitmap byte order mismatch fix by @nmvk (#3401)
+* Fix RDB expiry write length and leak when loading zipmap by @charsyam (#3422)
+* Fix slot-migration-max-failover-repl-bytes unable to accept -1 by @enjoy-binbin (#3443)
+* Fix config rewrite producing negative values for unsigned memory configs by @enjoy-binbin (#3440)
+* Fix trivial double-free issue in rdbLoadObject by @charsyam (#3453)
+* Fix incorrect memory overhead calculation for watched keys by @enjoy-binbin (#3359)
+* Fix VLA warning in linenoise and enable -Werror by @madolson (#3439)
+* Avoid having server.h being included by cli and benchmark by @ranshid (#3420)
+* Change rdbSaveStreamConsumers return type from size_t to ssize_t by @zuiderkwast (#3499)
+
 Valkey 9.1.0-rc1 - Released Tue Mar 17 00:00:00 2026
 -------------------------------------
 

src/version.h

@@ -10,7 +10,7 @@
  * In unstable branch the status is always "dev".
  * During release process the status will be set to rc1,rc2...rcN.
  * When the version is released the status will be "ga". */
-#define VALKEY_RELEASE_STAGE "rc1"
+#define VALKEY_RELEASE_STAGE "rc2"
 
 /* Redis OSS compatibility version, should never
  * exceed 7.2.x. */