Version 9.4 of Octez (the Tezos distribution at Tezos / tezos · GitLab) has just been released.
This version fixes an issue in the mempool that caused too many operations referring to unknown blocks to be kept, resulting in the node running out of memory.
Full changelog and update instructions will soon be available in the version 9 release page: Version 9.4 — Tezos (master branch, 2021/07/02 23:44) documentation
The Git tag for this release is
v9.4 and the corresponding commit hash is
latest-release now points to this new tag.