[Rspamd-Announce] Rspamd 2.7 has been released

[Andrew Lewis]

We have released Rspamd 2.7 today.

This is mostly a bug-fix release with no incompatible changes.

Here is a list of the major projects and serious bugfixes where applicable.

### Fixed issues with DKIM and ARC verification

It was possible for some DKIM checks to fail where multiple signatures  
are present due to a canonicalisation bug. This issue has now been  
fixed. Arc plugin has also been fixed to support certain CV values.

### Added support for S/MIME containers

 From this version, Rspamd supports .p7 containers and extracting  
signed parts during the checks. For details see the following issue.

### Several important rules rework

Anton Yuzhaninov has reworked many old rules in Rspamd improving their  
quality and has removed several outdated rules as well.

### Support of caching for regexp multimaps

Regexp maps can now be cached on disk which should improve loading  
speed of large maps on reload/restart of Rspamd if they are unchanged.

### Neural plugin offline learning

In this mode, Rspamd can train neural network from Clickhouse so it is  
possible to define better training conditions and manage learning for  
large systems with more fine grained control. Please refer to the  
corresponding documentation section for more details. Thanks to Andrew  
Lewis for implementing this functionality.

### Other changes

Here is the list of the important changes:

* [Conf] Add R_DKIM_PERMFAIL to the metric
* [CritFix] Dkim: Fix simple canonicalisation if multiple signatures  
are presented
* [CritFix] Fix controller paths normalisation
* [Feature] Add INVALID_DATE rule
* [Feature] Add controller endpoint for training neural
* [Feature] Add sanity checks for actions thresholds
* [Feature] Add support of '==' and '!=' in Rspamd expressions
* [Feature] Composites: Improve composite atoms parser
* [Feature] Docker: use Debian slim variant
* [Feature] Elastic: Add some missing fields
* [Feature] Extract text from img alt attributes
* [Feature] Improve charset detection logic
* [Feature] Lua_clickhouse: Add optional row callback for large selections
* [Feature] Lua_dns_resolver: Add idna_convert_utf8 method
* [Feature] Lua_mime: Add ability to do multipattern replacement
* [Feature] Lua_trie: Allow to report start of the match
* [Feature] Multimap: support adding map values as extra options
* [Feature] Neural: Move PCA learning to a subprocess
* [Feature] RBL: support matching content/image URLs only
* [Feature] RBL: support use of multiple selectors
* [Feature] Reputation: Allow to specify ip masks
* [Feature] Support SMIME signed messages container
* [Feature] Support multiple conditions for symbols
* [Feature] Support ping in milter mode
* [Feature] Support rspamd_text in selector regexps
* [Feature] Use own daemonization routine
* [Feature] Vadesecure: Implement settings_outbound feature as  
recommended by Vade
* [Feature] `rspamadm clickhouse` command
* [Feature] allow hyperscan for aarch64
* [Fix] Allow to set priorities between post init scripts
* [Fix] Allow to use maps for strings that are not zero terminated
* [Fix] Apply max_lua_urls limit for emails as well
* [Fix] Arc: Fix CV check on signing
* [Fix] Arc: Fix signing of the broken ARC chains
* [Fix] Clickhouse: escape carriage return
* [Fix] Composites: Allow partial match
* [Fix] Deduct type of a table methods
* [Fix] Do not load errored hyperscan database
* [Fix] Do not process links in ignored html tags
* [Fix] Fix ClamAV result for cached encrypted file (#3395)
* [Fix] Fix canonicalisation when l= tag is presented
* [Fix] Fix flag shift
* [Fix] Fix handling of skip/skip_process http flags
* [Fix] Fix html attachments checks
* [Fix] Fix issue with pushing binary formats to Lua strings
* [Fix] Fix logging for rspamadm
* [Fix] Fix off-by-one with init check
* [Fix] Fix parsing of escape characters in quoted pairs
* [Fix] Fix pushing ucl strings with \0 inside
* [Fix] Fix quoted-printable soft newlines bugged case
* [Fix] Fix settings in case actions are set to null (#3415)
* [Fix] Fix several issues with auth results producing
* [Fix] Fix smtp comments exclusion
* [Fix] Fix smtp date syntax definition
* [Fix] Fix substring search in case if srchlen == inlen
* [Fix] Fix text selectors
* [Fix] Honour `systemd` setting when logging to console (#3514)
* [Fix] Html: Add entities collisions prevention logic (e.g. for  
mathml entities)
* [Fix] Lua_auth_results: Quote potentially bad values in AR header
* [Fix] Multimap: Fix flags usage
* [Fix] Multimap: Fix scoring for combined maps
* [Fix] Plug GList * leak in redis pool
* [Fix] RBL: allow for multiple matches of the same label if types are  
different
* [Fix] Rely on libev checks for file maps
* [Fix] Restore simple dkim canonicalisation mode
* [Fix] Return MimeCharset as we work with emails...
* [Fix] Spamassassin: Fix pcre_only flags
* [Fix] Spamassassin: Preserve 'pcre_only' flag when dealing with  
regexp replacements
* [Fix] Try to fix GError leak
* [Fix] Try to fix a mess with settings loading by adding priorities
* [Fix] Try to move setings initialisation to a later stage
* [Fix] Use dup fd in milter handler to avoid races with the proxy
* [Fix] Use message pointer to avoid obsolete data to be cached
* [Project] Rbl: Migrate to `checks`
* [Project] Rbl: Move config code outside of the plugin
* [Project] Ressurect empty prefilters as connection filters
* [Project] Support connection filters registration from Lua
* [Rework] Add final cleanup logic
* [Rework] Add preliminary support of hyperscan caching for re maps
* [Rework] Add stale cache removal
* [Rework] Clickhouse: Improve performance
* [Rework] Distinguish between strict config test mode
* [Rework] Furhter logging improvements
* [Rework] Milter_headers: improve extended_headers_rcpt support
* [Rework] Move parsers to a separate lua library
* [Rework] Neural: Skip composite symbols
* [Rework] Rbl: Rework defaults logic
* [Rework] Some tunes to cache saving
* [Rework] Track maps origins
* [Rework] Use full crypto hash for regexp maps
* [Rules] Remove broken rule