[Mimedefang] error log after upgrade SpamAssassin

[Xiaoyan Ma]

I upgraded SpamAassassin from 2.44 to 2.55 and now I see these in the log:

Jul 13 11:18:18 mail-b-eth0 mimedefang-multiplexor: [ID 778059 mail.info] 
Starting slave 0 (pid 1327) (1 running): Bringing slaves up to minSlaves (4)
Jul 13 11:18:18 mail-b-eth0 mimedefang-multiplexor: [ID 260045 mail.error] 
Reap: Idle slave 0 (pid 1327) exited normally with status 1 (SLAVE DIED 
UNEXPECTEDLY)
Jul 13 11:18

Did I miss a step?  Do I need to reinstall Mimedefang after upgrade SA ?

Thanks.
Xiaoyan