Assegnate 5 su 5 stelle

Excellent!
It worked well for me in Thunderbird 52.9.1 (32-bit), but you have to know how:

Export:
In the Thunderbird Menu (click the 3 bars):
Manage Filters > Export Filters

Import:
If Menu Bar is not enabled, in the Thunderbird Menu (click the 3 bars):
Options > Menu Bar
on the Menu Bar:
Tools > Import Filters

Best of luck!
PT