To answer the first question: I would say if you need to keep to the old formatting for some reason, it's probably not worth the trouble of convertin a score to 2.0. As discussed elsewhere, 1.3 had a number of issues with layout that are fixed in 2.0, but fixing those issues does indeed mean layout will often be different, and any manual adjustments you employed in your 1.3 scores as workarounds for these issues will likely not make sense any more and end up being counterproductive. In some cases, we are able to recgonize this and throw away the no-longer-needed manual adjustments. But in other cases we can't be sure, so we keep them. So you might need to reset them manually once you load the score and see how things look.
So my standing recommendation is, forget you ever saw your scores in 1.3, reset manual adjustments such as stretch and manual line breaks, and take a fresh look at your scores in 2.0. Chances are excellent you will need no further adjustments - that you will be happy with the new defaults. But if you do decide you wish to go back in and adjust things to change the number of measures per system or whatever, you can now do so starting from the new defaults.
As for changes not "sticking", I'd say if you have some specific score where that appears to happen, then that is a bug that affects that prticular score or the particular adjustment you tried making, so you'd have to post it here with precise steps to reproduce the problem, as suggested above. For instance, there is a known bug in 2.0 - already fixed in the nightly builds - where adjustments to stem length don't survive save/reload. Maybe you are seeing that or one of the handful of simialr bugs already fixed. Or maybe you've encountered new one But in general, of coruse adjustments made should "stick".
Comments
modifications should stick, so if you find some that don't, report.
To answer the first question: I would say if you need to keep to the old formatting for some reason, it's probably not worth the trouble of convertin a score to 2.0. As discussed elsewhere, 1.3 had a number of issues with layout that are fixed in 2.0, but fixing those issues does indeed mean layout will often be different, and any manual adjustments you employed in your 1.3 scores as workarounds for these issues will likely not make sense any more and end up being counterproductive. In some cases, we are able to recgonize this and throw away the no-longer-needed manual adjustments. But in other cases we can't be sure, so we keep them. So you might need to reset them manually once you load the score and see how things look.
So my standing recommendation is, forget you ever saw your scores in 1.3, reset manual adjustments such as stretch and manual line breaks, and take a fresh look at your scores in 2.0. Chances are excellent you will need no further adjustments - that you will be happy with the new defaults. But if you do decide you wish to go back in and adjust things to change the number of measures per system or whatever, you can now do so starting from the new defaults.
As for changes not "sticking", I'd say if you have some specific score where that appears to happen, then that is a bug that affects that prticular score or the particular adjustment you tried making, so you'd have to post it here with precise steps to reproduce the problem, as suggested above. For instance, there is a known bug in 2.0 - already fixed in the nightly builds - where adjustments to stem length don't survive save/reload. Maybe you are seeing that or one of the handful of simialr bugs already fixed. Or maybe you've encountered new one But in general, of coruse adjustments made should "stick".