Hi,
I installed 10.3.1 without any problems. My machine is old and I still have Delphi XE, Berlin, Tokyo and Rio installed. I mostly use Tokyo, but I'm confident and I'm migrating my projects to Rio Update 1.
I use the migration tool to export my settings from 10.3 to a file. (Very important step!!!)
Used the feature install ( Tools -> Manage platform is present ). Emb. should change the way to distinguish between one and another. Messing up a delphi installation by using the wrong installer would cost at day or two to reinstall everything.
Selected "NO" since I WANT TO KEEP MY REGISTRY settings. Please consider change this too. Instead of YES or NO, please use something like: "Keep your settings" / "New installation".
Selected all the features I want installed
Waited for an hour
Clicked "Start working" and voilá(*)
*I was almost ready. Some components where there, but other no. Especially my Library path. This is why you need the migration tool. Import the file and you're done!
The 10.3.1 IDE is more stable than 10.3. This week I will migrate more projects and I will be able to compare against 10.2, but it seems 10.3.1 is a LOT better than 10.2
I'm working on a Win64 project (Multithreaded TCP/UDP communication with InterThread messaging).
With 10.3 I had 4 or 5 crashes a day. With 10.3.1 NONE ( so far ). With 10.2 I had to use IDE Fix pack (No crashes at all for days). So far I'm not using IDE fix pack in 10.3.1 and I don't feel like I need it.