Opening a 2.x score in 3.6 and choose 'Keep old style' does not keep the style.
In OS: Windows 7 SP 1 (6.1), Arch.: x86_64, MuseScore version (64-bit): 3.6.0, revision: e6b5adc
Opening a 2.x score and choose 'Keep old style' in the 'Try our improved style' dialog v2
does not keep the old style, new fonts and and new style are applied, all personal style setting should be manually reentered.
In the same manner, the choices in 'Preferences -> import -> Reset all positions' does nothing.