For Power 0.6.5
After a very long while, there is a new version of this campaign. Do note that it is only for Wesnoth 1.14, older versions are not supported anymore. Finally, a new scenario of Chapter 6 is here. No other change will beat this, I am going to list all significant changes below.
All campaigns now have difficulty, scenario count and add-on's version in their descriptions and they can be chronologically sorted (I added start_year and end_year for them but they are not 100% accurate). First chapter underwent some additional changes: dialogues in some of its scenarios were improved, the assassin is level 3 now (to be a bit harder to kill) and Glacyn cannot recruit level 0 units anymore.
A few units experienced small changes. Now all maximum level units with default amla require (their level * 50) experiences to reach an amla (just like in mainline). Lemyr as High Paladin in multiplayer needs 60 experiences for first amla. (Older) Jolla has got 2 new possible advencements (no spoilers, find out for yourself). Amiwen now goes with different traits - loyal and healthy and will get her first advancement after gaining 60 experiences. Aspirants (level 1 enemy units in Chapter 6) no longer have magical weapon special on their staves (it was not intentional).
Also leadership abilities should now work as intended and Warlord's Armor in Cave (Chapter 5) now provides leadership on the unit's level, not always 3.
And that is all worth mentioning. There were other changes under the hood. They were mostly internal but compatibility of saves from previous versions might have been broken.