Dovecot announcement on future feature removals

[plutocrat]

Not sure if this affects VestaCP, but just posting it here to put it on everyone's radar

Dovecot is now a nearly 20 year old product, and during that time it has accumulated many different features and plugins in its core repository.

We are starting to gradually remove some of these parts, which are unused, untested or deprecated.
We will provide advance notification before removing anything.

To start, the following features are likely to be removed in next few releases of Dovecot.

- Authentication drivers: vpopmail, checkpassword, bsdauth, shadow, sia
- Password schemes: HMAC-MD5, RPA, SKEY, PLAIN-MD4, LANMAN, NTLM, SMD5
- Authentication mechanisms: ntlm, rpa, skey
- Dict drivers: memcached, memcached-ascii (use redis instead)
- postfix postmap support
- autocreate & autosubscribe plugins (use built-in auto=create/subscribe setting instead)
- expire plugin (use built-in autoexpunge setting)
- fts-squat plugin
- mailbox alias plugin
- mail-filter plugin
- snarf plugin
- xz compression algorithm

For the authentication drivers that are being removed, we suggest using Lua as a replacement. See
https://doc.dovecot.org/configuration_m ... ntication/

For information about converting between password schemes, see
https://wiki2.dovecot.org/HowTo/ConvertPasswordSchemes

If you are using any of these features, please start preparing for their removal in the near
future. Features will begin to be dropped as of v2.3.11.

Additionally, the mbox format will no longer receive new development. It will still be
maintained, however its use beyond migrations and other limited use cases will be discouraged.

Please contact us via the mailing list if you have any questions.

Regards,
Dovecot Team