There is no automatic fix of the previously computed PSD values.
If you want the new values, you need to recompute the PSD files (connectivity measures are not affected). But this is not necessary, unless you are planning to compare new PSD values with old ones. You can keep using the "old" option in the PSD process to keep it compatible it with your previous results, this is totally fine.
The difference between the new "physical" units and the previous values (now option "old"), is a small scaling factor, uniform across all the channels. This has therefore no impact on statistics, or topographies.
Related discussions: