Competition changes:
*Brazilian Champions Cup disabled.
*International friendlies calendar rewritten and synced for all confederations: friendlies are now played on the same designated dates.
*Portuguese ProLiga restructured back to 18 teams (Taça de Portugal also accordingly edited).
*Republic Of Ireland season now takes place over a single calendar year, eg only 2018, then only 2019 etc.
*Russian season now takes place over two calendar years, eg 2018/19, then 2019/2020 etc.
*Russian Football National League restructured to 20 teams.

Minor competition changes:
*Champions League: Final now played on a Saturday.
*Confederations Cup code edited to ensure it takes place in 2021/2025 etc, host also changed from Russia to Qatar.
*Copa Libertadores: Knockout rounds now use away goals as a tiebreaker before penalties (except for the final, which now goes to extra-time before penalties).
*EFL Cup: Extra-time removed from all rounds apart from the Final (penalties if level after 90 minutes).
*French fixtures rescheduled in Ligue 1 & 2, in the former you should no longer have to play two matches on the same day.
*German DFB-Pokal: 3 non-EU player limit removed (now no limit).
*Irish Munster Senior Cup now searches for the Munster clubs' updated database names.
*Italian Serie A & B no longer use playoffs to determine the positions of teams who finish with equal points: they now use head-to-head results folllowed by goal difference (thanks gio!).
*Japanese Emperor's Cup now takes place throughout the year, rather than just December (where it clashed with the FIFA Club World Cup).
*Japanese J1 League Final second leg brought forward a few days to avoid a clash with the FIFA Club World Cup.
*Kypello Elladas: Semi Finals will no longer clash with European fixtures (the Final will also now be played on a Saturday).

Gameplay changes:
*International teams a bit more likely to call up players playing well in their own domestic leagues over reserves at clubs in higher level leagues.
*Regens now return with a higher level of Current Ability (also there should be fewer 20 year old regens).
*Under-21 caps are no longer binding: players can potentially play for a different nation in the future.

Minor gameplay changes:
*Argentinian foreign players allowed in matches & squads increased from 4 --> 5.
*French clubs can now no longer sign any players between the summer and winter transfer windows.
*Girona FC are now properly linked to their B team.
*Regens won't be assigned to clubs with 45+ players: previously they could be, potentially resulting in the club free transferring some decent youngsters already in their squad (thanks xeno!).
*Russia: Second nationalities will be gained after 5 years instead of 10.
*Scotland: Teams no longer have to upgrade to a 10,000 seater stadium when they're promoted to the Scottish Premiership. [v6]
*Turkish competitions' substitutes named increased from 7 --> 9.

Display changes:
*Rename v1.4.5 included.
*Version name updated in Game Settings screen.

Known issues introduced in v6:
*Republic Of Ireland still behaves like a winter league in places (contracts are negotiated to end in June instead of December).
*Republic Of Ireland's summer break is longer than real life as players stopped training in June.
*Russia still behaves like a summer league in places (contracts are negotiated to end in December instead of June).
*Under-21 caps: '(capped at U21 level)' will be shown after a player's second nationality regardless of which nation actually capped him.