{
  "schema_version": 2,
  "id": "operate/rs/release-notes/rs-6-4-2-releases/rs-6-4-2-81",
  "title": "Redis Enterprise Software release notes 6.4.2-81 (June 2023)",
  "url": "https://redis.io/docs/latest/operate/rs/release-notes/rs-6-4-2-releases/rs-6-4-2-81/",
  "summary": "Email alerts for database backup failures and replica high availability shard relocation failures.",
  "tags": [
    "docs",
    "operate",
    "rs"
  ],
  "last_updated": "2026-10-06T08:53:14-07:00",
  "page_type": "content",
  "content_hash": "d3ac0dc30a19f960ab4cca5f8891a0aed3150adf5c8925ce4c7931da0d8cfe0c",
  "sections": [
    {
      "id": "overview",
      "title": "Overview",
      "role": "overview",
      "text": "This is a maintenance release for ​[​Redis Enterprise Software version 6.4.2](https://redis.io/downloads/#software).\n\nThe following table shows the MD5 checksums for the available packages:\n\n| Package | MD5 checksum (6.4.2-81 June release) |\n|---------|---------------------------------------|\n| Ubuntu 16 | 31631248672de0154ec20aee0bff9adc |\n| Ubuntu 18 | eb4e8c1bc1443923ebcd457e51684f7e |\n| Ubuntu 20 | 1256292b8dca6456e69dc309be51a8d0 |\n| RedHat Enterprise Linux (RHEL) 7<br/>Oracle Enterprise Linux (OL) 7 | 1e51c5fdf22c0b6988565444ba08c6cd |\n| RedHat Enterprise Linux (RHEL) 8<br/>Oracle Enterprise Linux (OL) 8 <br/>Rocky Enterprise Linux | 96dc036339fe18fb218e8d4c8ff50c99 |\n| Amazon Linux 2 | 1a549bdb360c9e22ef764faeadbd4c90 |"
    },
    {
      "id": "new-features-and-enhancements",
      "title": "New features and enhancements",
      "role": "content",
      "text": "- RS77279 - Database backup failures and replica high availability ([replica HA](https://redis.io/docs/latest/operate/rs/databases/configure/replica-ha)) failures (for example, when relocating a shard from a node) now generate email alerts\n\n#### Redis Stack v6.2.6\n\nRedis Enterprise Software v6.4.2 includes the new features delivered in the latest [Redis Stack release (6.2.6 v6)](https://redis.com/blog/introducing-redis-stack-6-2-6-and-7-0-6/):\n\n- [RediSearch v2.6.9](https://redis.io/docs/latest/operate/oss_and_stack/stack-with-enterprise/search)\n\n- [RedisJSON v2.4.7](https://redis.io/docs/latest/operate/oss_and_stack/stack-with-enterprise/json)\n\n- [RedisBloom v2.4.5](https://redis.io/docs/latest/operate/oss_and_stack/stack-with-enterprise/bloom)\n\n- [RedisGraph v2.10.9](https://redis.io/docs/latest/operate/oss_and_stack/stack-with-enterprise/deprecated-features/graph)\n\n- [RedisTimeSeries v1.8.10](https://redis.io/docs/latest/operate/oss_and_stack/stack-with-enterprise/timeseries)\n\nSee [Upgrade modules](https://redis.io/docs/latest/operate/rs/installing-upgrading/modules/upgrade-module) to learn how to upgrade a module for a database."
    },
    {
      "id": "resolved-issues",
      "title": "Resolved issues",
      "role": "content",
      "text": "- RS101204 - Fixed high memory consumption that was caused by the `persistence_mgr` service when AOF persistence is configured for every second.\n\n- RS39322 , RS35526  - [`rlcheck`](https://redis.io/docs/latest/operate/rs/references/cli-utilities/rlcheck) no longer requires root privileges and can run with the `redislabs` group and user.\n\n- RS97315, RS100853  - Fixed the robustness of the support package process when collecting the shard configuration.\n\n- RS65110 - Fixed firewalld SELinux configuration.\n\n- RS101691 - Clean false error messages at the end of installation."
    },
    {
      "id": "known-limitations",
      "title": "Known limitations",
      "role": "content",
      "text": ""
    },
    {
      "id": "feature-limitations",
      "title": "Feature limitations",
      "role": "content",
      "text": "- RS78430 - When [tuning module arguments](https://redis.io/docs/latest/operate/rs/references/cli-utilities/rladmin/tune#tune-db), typos or unsupported arguments can cause shards to get stuck after restarting.\n\n- RS40641 - API requests are redirected to an internal IP in case the request arrives from a node which is not the master. To avoid this issue, use [`rladmin cluster config`](https://redis.io/docs/latest/operate/rs/references/cli-utilities/rladmin/cluster/config) to configure `handle_redirects` or `handle_metrics_redirects`."
    },
    {
      "id": "operating-system-limitations",
      "title": "Operating system limitations",
      "role": "content",
      "text": "#### Ubuntu 20.04\n\nBy default, you cannot use the SHA1 hash algorithm ([OpenSSL’s default security level is set to 2](https://manpages.ubuntu.com/manpages/focal/man3/SSL_CTX_set_security_level.3ssl.html#notes)). The operating system will reject SHA1 certificates even if the `mtls_allow_weak_hashing` option is enabled. You need to replace SHA1 certificates with newer certificates that use SHA-256. Note that the certificates provided with Redis Enterprise Software use SHA-256."
    }
  ],
  "examples": []
}