4.03 Theme Override - is it true?

If you setup a custom theme in 4.02 and then upgrade to 4.03 or the next upgrade do you lose your theme?

If so are there easy ways to recover your theme other than starting from the beginning?

All suggestions are very welcome - thank you!

I did not lose mine from 4.02 to 4.03 but wait for others to respond to see if they had any issues. Always backup before doing any upgrade

We did not lose any of ours. We went from 4.01 to 4.02 to 4.03 without any issues. Just a couple minor losses due to us not placing them in hooks…