Rene,
I want to make sure you understand that this is experimental software that is not yet released. I've tested best I can, and the next step moving towards a release is getting volunteers to use/test the software and (gently) feed back bugs and suggestions for improvements. You can be a tester if you like--in fact I'd love to have southern hemisphere testers.
Given that disclaimer, here are two possible ways to get the program (do one or the other):
1) Compile KStars from source. Many people who test early software on the forum have the capability to compile KStars. If that is you too, great! If you're not used to compiling software, probably best to try approach #2. To compile and install, follow the instructions in:
indilib.org/forum/general/210-howto-buil...st-libindi-ekos.html (probably you just need the KStars part).
In those instructions, I'd replace -DCMAKE_BUILD_TYPE=Debug with -DCMAKE_BUILD_TYPE=RelWithDebInfo
2) Download the "nightly build". See the "Nightly Builds" section in:
indilib.org/download.html. These instructions apply to Linux. I don't know how to get Mac or Windows nightly builds, but it may be possible--if someone knows, please reply. I just checked and this new polar-align code is included in the current nightly build for the Ubuntu 20.04 linux system I have. After you've installed, make sure that when you run kstars, in the KStars --> Help --> About KStars menu it says "Version 3.5.2 Beta".
Again, note that you'll be getting the latest experimental KStars and Indi code, not the more tested releases. You may get other changes besides this one.
You should be able to go back to the standard release following the instructions also on
indilib.org/download.html.
Feel free to follow-up if you have further questions,
Hy