Hi,
I installed SpamAssassin 2.53 from Greg Zartman / Shad Lords / James Price, which made no problem during the install.
But on the Save & Restart action, 2 problems appeared, concerning calls to esmith::ConfigDB and esmith::AccountsDB in the user templates 30spamassassin and 95saSort.
I fixed the problem in changing :
esmith::ConfigDB->open_ro() by esmith::ConfigDB->open()
esmith::AccountsDB->open_ro() by esmith::AccountsDB->open()
It now seems to work...

I didn't find the email addresses of the authors, that's why I thought it was a good idea to describe the problem and its fix here.
Hope it helps,
Erika