While testing a test version of Net::DNS which is version 1.40_02 I encountered an error in DKIM/PublickKey.pm where it checks the version. Also, see issue #8 in which the actual problem was the same bug in SpamAssassin that I have fixed in the upcoming 4.0.1 release, although your workaround in DKIM avoids the bug in SpamAssassin and is fine.
The correct way to check versions in perl is to add
While testing a test version of Net::DNS which is version 1.40_02 I encountered an error in DKIM/PublickKey.pm where it checks the version. Also, see issue #8 in which the actual problem was the same bug in SpamAssassin that I have fixed in the upcoming 4.0.1 release, although your workaround in DKIM avoids the bug in SpamAssassin and is fine.
The correct way to check versions in perl is to add
use version;
(See https://metacpan.org/pod/version) and then change line 107 to do the version comparison like this
if ( version->parse(Net::DNS->VERSION) >= version->parse(0.69) )