Important changes since 3.0.2:
[Fix] Correctly set topic starter if first post in topic removed (Bug #30575 - Patch by blueray2048)
[Fix] Added VST - Venezuela Standard Time (Bug #30545).
[Fix] Close DB connections in file.php.
[Fix] Correctly return results for nested cached queries (Bug #31445 - Patch by faw).
[Fix] Allow export of PM pages greater one. (#33155)
[Fix] Display coloured username of last poster in list of subscribed forums (prosilver).
[Fix] Do not jump back to page 1 when hiding member search in memberlist. (Bug #32515)
[Fix] Correctly limit input of the users location to 100 characters in the UCP and ACP. (Bug #32655)
[Fix] Sync reports when using the move all users posts tool in the ACP. (Bug #31165)
[Fix] Remove reported flag from shadow topics when closing reports. (Bug #19765)
[Fix] Do not show non indexed forums on the search page if they contain no subforums. (Bug #33125)
[Fix] Stop search bots incrementing topic views. (Bug #32675 - Patch by eviL<3)
[Fix] Use correct link for post author search. (Bug #32595)
[Fix] Do not decrease topics counter when deleting shadow topics. (Bug #26495)
[Fix] Send localised disapproval reasons in the recipients local language. (Bug #31645)
[Fix] Do not display reported topic icon for shadow topics. (Bug #13970)
[Fix] Expand shown ban reason in unban screen to fully show long entries. (Bug #16234)
[Fix] Preserve alpha transparency for created thumbnails. (Bug #16575)
[Fix] Use correct port delimiter for MSSQL connections in windows. (Bug #16615)
[Fix] Do not allow setting forums parent to the forum itself. (Bug #18855)
[Fix] Display assigned rank/avatar for guests. (Bug #19155)
[Fix] Set secure cookie for style switcher if required. (Bug #19625)
[Fix] Fix native full text search on postgresql while using excluding keyword matches. (Bug #19195)
[Fix] Pass S_SEARCH_ACTION through append_sid() in search.php. (Bug #21585)
[Fix] Correctly handle unread status of subforums (that are not shown on the index) of forums that are shown on the index. (Bug #14589)
[Fix] Stop users from deleting posts after the edit time has passed or they have been locked. (Bug #19115)
[Fix] Split posts target forum requires 'f_post' now instead of 'm_split'. (Bug #31015)
[Fix] Use a distinct log message for shadow topic deletions to differentiate between normal topic deletions. (Bug #34635)
[Fix] Fix problems with styles using an underscore within the filename. (Bug #34315)
[Fix] Better return links when deleting topics through the MCP. (Bug #34655)
[Fix] Add quoting support to PM history when composing a reply. (Bug #34285)
[Fix] Use phpBB 3.1.x method for storing cached data to prevent PHP bug with our usage of var_export(). (Thanks to Techie-Micheal and HoL for pointing out possible problems)
[Fix] Check users pm preferences for pm's sent to groups. (Bug #33245)
[Fix] Do not allow password reminders if u_passchg permission is not given. (Bug #14806)
[Fix] Implemented strict check for cached user permissions and existing ACL options. This fix makes sure cached permissions are valid, even if they got already cached.
[Fix] Do not show link to user/group profiles if user has no permission to view the linked page and gets a denied message anyway. (Bug #15088)
[Fix] Do not display last post link and sort display options for search engines. (Bug #15088)
[Fix] Make sure users still get notifications if they set to only be notified by Jabber, but Jabber service disabled. (Bug #29715 - Patch by Paul)
[Fix] Don't show forum subscription link on categories. (Bug #34895)
[Fix] Display a message if no topics or forums are selected when unsubscribing. (Bug #34855)
[Fix] Mark/unmark all links in UCP now select/unselect both subscribed topics and forums.
[Fix] Increase board topic counter when splitting topics. (Bug #32125)
[Fix] Display profile icons when viewing a topic, or PM when only the jabber icon is to be visible. (Bug #34755)
[Fix] Do not send PMs with warnings if the user cannot read PMs or they are disabled. (Bug #30815)
[Fix] Correctly convert Niels' Birthday MOD to the date format used in phpBB3. (Bug #32895)
[Fix] Parse BBCode lists of type square, circle and disc. (Bug #35295)
[Fix] Round the displayed percentages in polls. (Bug #32375)
[Fix] Disable mass e-mail when e-mail is disabled. (Bug #27385)
[Fix] Display coloured poster username of queued posts displayed on the front of the MCP.
[Fix] Moderators can only see reports/queue/logs from forums they can actually read. (Bug #31085)
[Fix] Correctly display topic when start parameter is equal to the number of posts.
[Fix] Correctly display topic in MCP when start parameter is equal to or greater than the number of posts. (Bug #30525)
[Change] No longer allow the direct use of MULTI_INSERT in sql_build_array. sql_multi_insert() must be used.
[Change] Display warning in ACP if config.php file is left writable.
[Change] More restrictive chmod to new files being created. (phpbb_chmod() function mostly by faw)
[Change] Set headers to allow browsers to better cache attachments (Mylek pointed this out)
[Change] Hide parameters if they equal the default in viewforum/viewtopic (Bug #31185)
[Change] Various improvements to group listings (Bugs #32155, #32145, #32085, #26675, #26265)
[Change] Set headers for IE 8 in file.php
[Change] Do not count queued posts to user_posts.
[Change] Allow setting birth year to current year.
[Change] Do not use the topics posted table when performing an egosearch.
[Change] Log the forum name that topics are moved into.
[Change] Automatically add users/groups to the PM recipient list, if entered or selected.
[Change] Reply to PM now includes all previous recipients and not only the original sender.
[Change] Make topic selection for merge less confusing by removing unneeded controls. (Bug #21925)
[Change] MCP topic view checkboxes now default to unchecked.
[Change] Adjust language key "SPLIT_AFTER" to make the action clearer.
[Change] Add links to the post and forum when viewing a report from the MCP. (Bugs #33795, #33805)
[Change] Remove NUL-Bytes directly in request_var() for strings and within the custom DBAL sql_escape() functions (MSSQL, Firebird, Oracle) (reported by AdhostMikeSw)
[Feature] Allow limited inheritance for template sets.
[Feature] Allow hard disabling of the template editor.
[Feature] Allow setting custom language path through $user->set_custom_lang_path(). $user->lang_path now also do not include the user language, but only the path.
[Feature] Ability to define nullar/singular/plural language entries
[Feature] Ability to mimic sprintf() calls with $user->lang() with the ability to correctly assign nullar/singular/plural language entries.
[Feature] Added the possibility to force user posts put in queue if post count is lower than an admin defined value. Guest posting is not affected by this setting.
[Feature] Added 'max_recipients' setting for private messages. This setting allows admins to define the maximum number of recipients per private message with a board-wide setting and a group-specific setting.
[Feature] Added new permission setting for sending private messages to groups. Now there are two permissions to define sending private messages to multiple recipients and private messages to groups.
[Feature] Allow specific connection to different server for jabber functionality by providing a valid JID as username. This also allows the use of talk.google.com as jabber server with gmail.com JIDs. (Bug #14989)
[Sec Precaution] Stricter validation of the HTTP_HOST header (Thanks to Techie-Micheal et al for pointing out possible issues in derived code)
[/spoiler] наверное лучше не трогать пока ничего, а то многое на форуме просто перестанет работать...