Capella 1.4.1 has been released.
The release notes for Capella 1.4.1 is available on this Wiki page 
Capella 1.4.1 is available for download on the Capella website 
Weel done guys!
Hello all together,
What about the AddOns? Can the 1.4.0-Versions (there are no newer available yet) be used with Capella 1.4.1 (and 1.4.2 in the future)?
(once there was a compatibility-matrix - can not find it…)
Model-Migration: can e.g. a 1.3.1 model be migrated directly to 1.4.1 or has it to be migrated first to 1.4.0?
Here is the link to the compatibility matrix: https://wiki.eclipse.org/Capella/Addons but it won’t give you much answers to your question.
Here is the level of info I have:
For capella 1.4.1, you should take the 1.4.1 version of the add-ons if there is one, otherwise the 1.4.0 version. The 1.4.1 version of the addons have not been moved to the release directory, so you should look for them in the “stable” directory. Example:
Please also note that there is a Capella 1.4.2 version which is about to be released, coming with a few interesting bug fixes: https://github.com/eclipse/capella/releases/tag/v1.4.2-S20201014 :
Richtext edition improvements
Some of the addons are going to be released for Capella 1.4.2: docgen xhtml, filtering, system to sub-system transition but the rest of them that were working with 1.4.1 will work with 1.4.2
I hope this helps
I forgot your second question. I advise to do first the migration to 1.4.0 and then the migration to 1.4.1.