The RFC ({T259771}) has been approved and [[https://gerrit.wikimedia.org/r/c/648576|the patch]] to implement it has been merged. All these patch files, and associated logic, supporting versions upgrade upto 1.27 can now be removed
[x] 1.2
[x] 1.3
[x] 1.4
[x] 1.5
[x] 1.6
[x] 1.7
[x] 1.8
[x] 1.9
[x] 1.10
[x] 1.11
[x] 1.12
[x] 1.13
[x] 1.14
[x] 1.15
[x] 1.16
[x] 1.17
[x] 1.18
[x] 1.19
[x] 1.20
[x] 1.21
[x] 1.22
[x] 1.23
[x] 1.24
[x] 1.25
[x] 1.26
[x] 1.27
Additionally, these helper methods will also be dropped without deprecation. They're (all?) protected and are not supposed to be used outside their classes
[] MysqlUpdater::doInterwikiUpdate (1.2) (see T273080)
[] MysqlUpdater::doOldLinksUpdate (1.3)
[x] MysqlUpdater::doFixAncientImagelinks (1.3)
[] MysqlUpdater::doWatchlistUpdate (1.4)
[x] MysqlUpdater::doSchemaRestructuring (1.5)
[] MysqlUpdater::doNamespaceSize (1.5)
[x] MysqlUpdater::doPagelinksUpdate (1.5)
[x] MysqlUpdater::doUserUniqueUpdate (1.5)
[x] MysqlUpdater::doUserGroupsUpdate (1.5)
[x] MysqlUpdater::doWatchlistNull (1.6)
[] MysqlUpdater::doPageRandomUpdate (1.6)
[x] MysqlUpdater::doTemplatelinksUpdate (1.6)
[x] MysqlUpdater::doBacklinkingIndicesUpdate (1.9)
[x] MysqlUpdater::doRestrictionsUpdate (1.10)
[x] MysqlUpdater::doCategorylinksIndicesUpdate (1.11)
[] MysqlUpdater::doCategoryPopulation (1.13)
[] MysqlUpdater::doPopulateParentId (1.13)
[x] MysqlUpdater::doFilearchiveIndicesUpdate (1.13)
[] MysqlUpdater::doUpdateMimeMinorField (1.16)
[] MysqlUpdater::doClFieldsUpdate (1.17)
[] MysqlUpdater::doUserNewTalkTimestampNotNull (1.18)
[] MysqlUpdater::doIwlinksIndexNonUnique (1.22)
[] MysqlUpdater::doExtendCommentLengths (1.25)
[x] SqliteUpdater::sqliteInitialIndexes (1.14)
[x] SqliteUpdater::sqliteSetupSearchindex (1.16)
[] PostgresUpdater::convertArchive2
[] PostgresUpdater::checkOiDeleted
[] PostgresUpdater::checkOiNameConstraint
[] PostgresUpdater::addInterwikiType (r81574)
[] PostgresUpdater::tsearchFixes
[] PostgresUpdater::changeFieldPurgeTable (1.23)
[] PostgresUpdater::rebuildTextSearch (1.23.9)
[] DatabaseUpdater::doLogUsertextPopulation
[] DatabaseUpdater::doActiveUsersInit
[] DatabaseUpdater::doLogSearchPopulation
[] DatabaseUpdater::doMigrateUserOptions
[] DatabaseUpdater::doCollationUpdate