Header and Footer Text is not identical to 3.5 scores when opened in 3.6

Same problem; my header and footer settings never save, along with a few other things (hairpins don't stay at the default +-3.50 Y?).

Regarding the original problem with header and footer in scores imported from earlier version - please attach a score you are having trouble with. In my tests this works as expected, with one exception. If you happen to customize a style setting to be different from the 3.5 default but the same as the 3.6 default, then when importing into 3.6, MuseScore is confused and reverts to the 3.5 default. See #315006: Headers in imported 3.5.2 files are lost (perhaps due to style properties being reset to default in the RC). But other than that one case, everything else should work fine. So if you are experiencing a problem other than this, we would need a sample score.

As for any unrelated problem with settings not saving, or anything at all to do with hairpins, we would also need sample scores and precise steps to reproduce those problems. but please do so in a separate forum thread.

What are the defaults for 3.5.2 and 3.6? I'm trying to test the defaults but I can't tell if I'm setting stuff to be different from those.

Default for what, specifically? Header and footer fonts? FreeSerif, 8 pt. Presumably you have 3.6 and can see the new defaults for yourself, but for the record, both are Edwin; header is 11 pt bold, footer is 9 pt normal. But if you don't have both installed, there is no way for you to test this - the problem only occurs when saving scores in 3.5 and then opening them in 3.6. If you have a score that you believe exhibits a problem, just attach it and we can test further from there.

Yea, I meant the header/footer styling. I'm working on a 3.6 copy of a score I created last fall that I have kept up the updates with ever since. I want to keep the header at 10 pt. and footer at 8 pt. but upon saving, it regresses when I open it again. Same goes with hairpins (they regress to Y: 2 sp. rather than the original Y: 3.5 sp. which I think is the default, at least for pre-3.6.) and page numbers (I like them on the bottom center, but it keeps adding the top right one after every save). I'm not saving anything in 3.5; everything is running on the 3.6. If this sounds like something else I'll try to create a sample score.

So indeed, if this is all in 3.6, it's unrelated to the issue here, which is about scores created in 3.5 and imported into 3.6. Please start a new thread and attach the actual score with a problem, plus precise steps to reproduce the problem. It doesn't happen for most scores, something must be unique about yours in particular, which is why we need you to attach it.

Made an issue post including this: https://musescore.org/en/node/315847

Better #315847: Certain Formatting Changes/Resets Do Not Save in Parts

These are the font face and size settings

      <headerFontFace>Al Bayan</headerFontFace>
      <headerFontSize>11</headerFontSize>
      <footerFontFace>Al Bayan</footerFontFace>
 <xml>
No size setting for footer, so the default is taken, that in turn had changed from  8pt to 9pt
 
New Header default is indeed bold, but in that score it isn't set to that, so I don't get what your issue is about?

It isn't set to bold when I open that score in 3.6

Except in parts, but that is dealt with in #315847: Certain Formatting Changes/Resets Do Not Save in Parts

No problem these thing do happen