---
Title: Redis Enterprise Software release notes 6.4.2-81 (June 2023)
alwaysopen: false
categories:
- docs
- operate
- rs
compatibleOSSVersion: Redis 6.2.10, 6.0.17
description: Email alerts for database backup failures and replica high availability
  shard relocation failures.
linkTitle: 6.4.2-81 (June 2023)
toc: 'true'
weight: 68
---

This is a maintenance release for ​[​Redis Enterprise Software version 6.4.2](https://redis.io/downloads/#software).

The following table shows the MD5 checksums for the available packages:

| Package | MD5 checksum (6.4.2-81 June release) |
|---------|---------------------------------------|
| Ubuntu 16 | 31631248672de0154ec20aee0bff9adc |
| Ubuntu 18 | eb4e8c1bc1443923ebcd457e51684f7e |
| Ubuntu 20 | 1256292b8dca6456e69dc309be51a8d0 |
| RedHat Enterprise Linux (RHEL) 7<br/>Oracle Enterprise Linux (OL) 7 | 1e51c5fdf22c0b6988565444ba08c6cd |
| RedHat Enterprise Linux (RHEL) 8<br/>Oracle Enterprise Linux (OL) 8 <br/>Rocky Enterprise Linux | 96dc036339fe18fb218e8d4c8ff50c99 |
| Amazon Linux 2 | 1a549bdb360c9e22ef764faeadbd4c90 |

## New features and enhancements

- RS77279 - Database backup failures and replica high availability ([replica HA]({{< relref "/operate/rs/databases/configure/replica-ha" >}})) failures (for example, when relocating a shard from a node) now generate email alerts

#### Redis Stack v6.2.6

Redis 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/):

- [RediSearch v2.6.9]({{< relref "/operate/oss_and_stack/stack-with-enterprise/search" >}})

- [RedisJSON v2.4.7]({{< relref "/operate/oss_and_stack/stack-with-enterprise/json" >}})

- [RedisBloom v2.4.5]({{< relref "/operate/oss_and_stack/stack-with-enterprise/bloom" >}})

- [RedisGraph v2.10.9]({{< relref "/operate/oss_and_stack/stack-with-enterprise/deprecated-features/graph" >}})

- [RedisTimeSeries v1.8.10]({{< relref "/operate/oss_and_stack/stack-with-enterprise/timeseries" >}})

See [Upgrade modules]({{< relref "/operate/oss_and_stack/stack-with-enterprise/install/upgrade-module" >}}) to learn how to upgrade a module for a database.

## Resolved issues

- RS101204 - Fixed high memory consumption that was caused by the `persistence_mgr` service when AOF persistence is configured for every second.

- RS39322 , RS35526  - [`rlcheck`]({{< relref "/operate/rs/references/cli-utilities/rlcheck" >}}) no longer requires root privileges and can run with the `redislabs` group and user.

- RS97315, RS100853  - Fixed the robustness of the support package process when collecting the shard configuration.

- RS65110 - Fixed firewalld SELinux configuration.

- RS101691 - Clean false error messages at the end of installation. 

## Known limitations

### Feature limitations

- RS78430 - When [tuning module arguments]({{< relref "/operate/rs/references/cli-utilities/rladmin/tune#tune-db" >}}), typos or unsupported arguments can cause shards to get stuck after restarting.

- 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`]({{< relref "/operate/rs/references/cli-utilities/rladmin/cluster/config" >}}) to configure `handle_redirects` or `handle_metrics_redirects`.

### Operating system limitations

#### Ubuntu 20.04

By 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.