Version 1.14.6 is out

Fixed crash when the AI simulates a fight between two units which can slow but aren't yet slowed, then simulates another fight for one of them in Monte Carlo mode (issue #3650).
Experimental AI recruiting: fixed AI crash for unit type with unknown race
Support for modifying the available AIs using cores:
- New parameter default_ai_algorithm for setting the default AI
- New parameter mp_rank for setting the order in which AIs appear in the MP computer player selection menu

New option "Keep saved AI" when reloading games from the MP Create Game screen. Choosing this option prevents overwriting of the saved AI by the default AI. (issue #3791)
Forest Animals Micro AI: fix AI crash when using custom rabbit hole image
Fix Lua AIs using the ai.stopunit_*() functions potentially creating infinite candidate action loops

Campaigns

Dead Water:
- S12: Slightly rebalanced enemy reinforcements and ai gold

Descent Into Darkness:
- Allow converting L3 necromancers to liches from S12 onwards (issue #3165).
- Added an alternative method of completing the campaign (issue #3167).
- S8, S9 (A Small Favor II & III): Clarify objectives. (PR #3711)
- S8 (A Small Favor II): Fixed units created via the plague ability not available in S9. (PR #3711)

Sceptre of Fire:
- S1&2: increased difficulty
- S6: additional guards for the elves

Secrets of the Ancients:
- S01 Slipping Away: It is now obvious that the wild animals cannot cross the fences.
- S02 Dark Business: Simplify scenario by removing the temporary invisible starting keep.
- S05 Blackwater: Additional dialog from Ardonna at the start.
- S11 Battleground: Ghosts are now able to be recruited after the scenario is complete.
- S15 Mountain Pass: Bird bones moves so bird is easier to keep alive when discovered.
- S21 Against the World: Leader of the elves is now same elf from S12.
- S21 Against the World: Adjustment so player doesn't have to chase down some leaders at the end.
- Proper animation for finding the bird bones.
- Newly made liches will now receive a move point upon transformation if they weren't recalled. this turn and haven't moved yet.

The Hammer of Thursagan
- S12 'The Underlevels': redesigned with completely new map and scenario

Northern Rebirth:
- Fix loyal units obtained in S7 costing upkeep (introduced in 1.14.5)
- S13: Improvement to the AIs

The Rise of Wesnoth:
- S15: victory text is not used upon hero death
- S17d: enemy units are killed upon victory except for bats
- S22: cuttlefish now have the loyal icon

The South Guard:
- Revised scenario and story dialogue.
- Reworked and rebalanced all scenario and map designs.
- Removed S6a 'Tidings Good and Ill'.

Tutorial:
- S2: Wolf riders are not initially recruited, to not hinder the player from reaching the island in time

Language and i18n

Updated translations: British English, Chinese (Simplified), Chinese (Traditional), Czech, French, German, Italian, Japanese, Lithuanian, Russian, Scottish Gaelic, Slovak, Spanish, Ukrainian.

Lua API

Fix wesnoth.set_dialog_callback calling the function immediately when used in the previous callback. (issue #3794)
Fix wesnoth.set_dialog_value not triggering re-layout. (issue #3572)
wml.tostring() now outputs a string that can be parsed back to WML without loss of data.

Miscellaneous and bug fixes

Fix crash with custom themes on desktop PCs. (issue #3599)
Add --campaign-skip-story command line switch for skipping directly to turn 1. (issue #3472)
Remove --data option, --data-path has the same functionality.
Fix documentation of --render-image command line switch. (issue #3568)
Update manpage with options previously only documented by wesnoth --help.
Fix wrong ordering for BW / BF years, for example in Play a Campaign when sorted by date. (issue #3187)
GUI.pyw can now terminate a running maintenance script
Fix SDL_DestroyRenderer assertion failure under XMonad. (part of issue #3716)
Fix map item names not being translated in the scenario editor.
Usernames specified in the MP UI and command line are now stripped of leading and trailing whitespace, including newlines.
Show ability of a selected unit as active/inactive with respect to mouseover hex. (issue #3912)
macOS: Wesnoth now uses the app sandboxing feature, which means there is a new location for saves. All saves will be migrated during first launch automatically. For info about backwards compatibility see: https://gist.github.com/hrubymar10/eb5afd896f933a46fac344ced940e020
Many units lacking animations now have at least a defense animations

Multiplayer server

Fix stale temporary bans continuing to have an effect on players until cleared by phpBB on the next ban/unban operation.

Packaging

new scons option, intended to be used when building releases inside a git repo: autorevision=False
Fix build with Boost 1.69. (issue #3646)
Fix build with Pango 1.43. (issue #3840)

User interface

Fix regression: Game Load screen would not select 1.12 savegames. (issue #3561)
Fix regression: the in-game "Observers" icon (an eye) was covered by the minimap. (issue #3543)
Increase step size when clicking sliders in the MP Create Game dialog. (issue #3552)
Fix overlapping top bar elements with small screen resolutions. (issue #3714)
Don't scroll to an invisible unit that recruits another invisible unit. (issue #3559)
When a recruited unit is fogged, scroll to the recruiting unit and play recruit animation. (issue #3577)
Fix line breaks in first statistics line in unit type pages in the help. (issue #3256)
Don't scroll to an enemy unit that teleports to or from an invisible hex. (PR #3578)
Don't show in the sidebar the time of day schedule of a shrouded hex. (PR #3638)
Game Load screen gracefully handles savefiles that can't be parsed. (issue #3652)
The sidebar now shows alignment and damages as they would be on the hex under the mouse, rather than at the unit's current location. (PR #3642)
When a unit has multiple statuses (slowed/poisoned/invisible/etc), the sidebar shows all of them, not just the first. (issue #3197)
Fixed being able to dismiss a game lobby by pressing Esc.
Fixed multiple severe issues in the classic theme.
The "Attack Enemy" dialog now shows inactive weapon specials in gray. (PR #3686)
Taking screenshots in title screen is possible again (issue #3235)
The "Recruit Unit" dialog is searchable by unit type name. (PR #3787)
Add text filter to hotkeys preferences. (PR #3759)
Hide leader in status table if it's unfogged but invisible. (PR #3854)
macOS: Dark GUI on macOS Mojave and later when dark appearance is enabled.