Retiring Let’s Encrypt Testflume and Oak 2019/2020 CT shards

Hi everybody,

Let's Encrypt will be freezing and eventually deleting the following CT shards. These particular shards have long since stopped accepting new certificate issuances. This data purge will free up disk space for future shards, reduce replication time to new databases, and reduce Let’s Encrypt operating costs.


  • Testflume 2019
  • Testflume 2020
  • Oak 2019
  • Oak 2020

We will freeze the aforementioned shards on March 1st, 2021. Freeze means setting these shards to read-only mode also known in the Trillian software as a “soft delete”. Users will still be able to hit RFC 6962 get-* endpoints on these particular shards and have data returned. On April 1st, 2021 the shards will be automatically garbage collected by Trillian and “hard deleted”. Users will be unable to request data from the listed shards after the hard deletion.

Google has graciously provided the ecosystem with read-only log mirrors for production logs (e.g. Oak and NOT Testflume). Users are welcome to continue retrieving shard data from these mirrors. Please keep in mind that Google has not published any SLA or guarantee about the lifecycle of these mirrors.

This is cross-posted to