Fixed trouble when a new city is founded to the ruins of a former city,
and that new city establish a trade route with a player who had seen
former city, and is unaware that it had been destroyed HRM#871606
Fixed a case where shared vision did not completely update
recipient's map HRM#846106
Fixed a bug where one could paradrop to peaceful nation's territory
after continuing game from an old savegame HRM#879084
Fixed a bug causing game sometimes to tell wrong reason of why an
action failed HRM#879880
Cease fire no longer runs out with an already dead player, making his
former allies to hate the alive party of the treaty HRM#879055
Made server not to end in a infinite loop after loading savegame with
too high phase number. Such a savegame was reported to be created
after spaceship was launched but game was still continued HRM#815196
Unified writing of the city name Washington-on-the-Brazos
between rulesets, so it doesn't appear multiple times in the same
game in a bit different form HRM#867817
Stealth units are no longer erroneously hidden even from allies
HRM#764976
Placing initial units is now done in shuffled player order HRM#850656
Corrupt worker tasks are cleared. Those can originate, e.g.,
from buggy pre-2.6.2.1 Qt-client, and live in old savegames HRM#901938
In a ruleset, such as civ2civ3, where caravans can help building wonder
in a foreign city, refresh city info of the city owner when one does
HRM#907977
Display of success probabilities for diplomats was off when targeting
stack of units instead of individual unit HRM#859761
Fixed pillaging of extras that are caused by something else than
player actions. For the fix to work, both server and client must be
at least version 2.6.3 HRM#861508
Civilian unit trying to paradrop to an enemy city dies HRM#870004
Prevented dead player from getting techs via Tech_Parasite effect.
This caused trouble in alien ruleset where Tech_Parasite is granted
by a tech HRM#873692
Improved support of CityTile requirement type HRM#877780
Fixed trouble preventing Small Wonders from working as impr_reqs
for units HRM#884993
Corrected success probability shown by action dialog when it depends
on a special kind of road HRM#897490
The included Lua engine has been upgraded from 5.3.5 to 5.3.6. HRM#889425
update to 2.6.2.1:
Fixed server crash when unit with zero move_rate is transformed
Fixed crashes when using Direction objects in lua scripts
Fixed crash when chatline text had opening tag without closing tag
Fixes to the Qt client
Updated translations
Fixed Qt-client build against Qt-5.15 (removes freeciv-qt-5.15.patch )