diff --git a/CHANGELOG.md b/CHANGELOG.md
index e72c126..e1b2750 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/), and this
 
 ## [Unreleased]
 
+## [5.9.1] - 2026-05-01
+
+### Added
+
+- **CRC64-NVME checksum support** — added support for the `crc64-nvme` checksum algorithm across all S3 drivers (Netty, AWS SDK, and RDMA). The Netty driver now includes explicit checksum strategy metadata and multipart checksum wiring for CRC64-NVME. The CLI `--checksum crc64-nvme` flag is now accepted for all S3 drivers (previously AWS-only). Added RDMA checksum parity tests covering CRC32, CRC32C, and CRC64-NVME known vectors. (PRs #101, #102)
+
 ## [5.9.0] - 2026-04-29
 
 ### Added
diff --git a/VERSION b/VERSION
index b3d91f9..9266671 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-5.9.0
+5.9.1
\ No newline at end of file
diff --git a/engine/core/spt-base/src/main/resources/config/defaults.yaml b/engine/core/spt-base/src/main/resources/config/defaults.yaml
index d0f05a0..0c8d122 100644
--- a/engine/core/spt-base/src/main/resources/config/defaults.yaml
+++ b/engine/core/spt-base/src/main/resources/config/defaults.yaml
@@ -117,7 +117,7 @@ run:
   node: false
   port: 9999
   scenario: null
-  version: 5.9.0
+  version: 5.9.1
 
 log:
   level: info