Continuing the discussion from Exporting/Importing Blacklist:
On the old server…Highlite the list in the Blacklist page, copy/paste them to a fresh spreadsheet. Save as .csv
On the new server use 12.0.X and it has an import from .csv function built in, select the file you made and import it.
I just moved all my blacklist numbers in baout 3 minutes.
JayArr