v3.10 adds group conversations while resolving other bugs and QOL changes. It is potentially breaking to some plugins that adds functionality to threads.

Breaking

• Thread.recipient (str) is now Thread.recipients (List[str]).
• Thread.reply now returns mod_message, user_message1, user_message2... It is no longer limited at a size 2 tuple.

Added

• Ability to have group conversations with up to 5 users. (GH [#143])
• Snippets are invoked case insensitively. (GH [#3077], PR [#3080])
• Default tags now use top hoisted role. (GH [#3014])
• New thread-related config - thread_show_roles, thread_show_account_age, thread_show_join_age, thread_cancelled, thread_creation_contact_title, thread_creation_self_contact_response, thread_creation_contact_response. (GH [#3072])
• use_timestamp_channel_name config to create thread channels by timestamp.

Improved

• ?contact now accepts a role or multiple users (creates a group conversation). (GH [#3082])
• Aliases are now supported in autotrigger. (GH [#3081])

Fixed

• Certain situations where the internal thread cache breaks and spams new channels. (GH [#3022], PR [#3028])
• Blocked users are now no longer allowed to use ?contact and react to contact. (COMMENT [#819004157], PR [#3027])
• UnicodeEncodeError will no longer be raised on Windows. (PR [#3043])
• Notifications are no longer duplicated when using both ?notify and subscribe. (PR [#3015])
• ?contact now works properly with both category and silent. (GH [#3076])
• close_on_leave_reason now works properly when close_on_leave is enabled. (GH [#3075])
• Invalid arguments are now properly catched and a proper error message is sent.
• Update database after resetting/purging all plugins. (GH [#3011])
• thread_auto_close timer now only resets on non-note and replies from mods. (GH [#3030])
• Deleted messages are now deleted on both ends. (GH [#3041], @JerrieAries)
• Persistent notes are now properly deleted from the database. (GH [#3013])
• Modmail Bot is now recognized to have OWNER permission level. This affects what can be run in autotriggers.

Internal

• Fix return types, type hints and unresolved references (PR [#3009])
• Reload thread cache only when it's the first on_ready trigger. (GH [#3037])
• format_channel_name is now extendable to plugins. Modify Bot.format_channel_name(bot, author, exclude_channel=None, force_null=False):. (GH [#2982])