Which critical bugs are you referring to and do they still exist in Build 8993?

I didn't see any fixes for them in the change log. The first is the pop3 retriever deadlock and the second is for anti-spam

Hi, Michael

Regarding these issues:

1. The antispam issue you're referencing isn't a bug. Trusted Senders still require the sender to pass SPF, DKIM, and DMARC. If they do not pass these checks, email from a Trusted Sender can still be marked as Junk Email. We have added a setting where users can bypass these checks for "unverified senders", and we've mentioned this to you in your tickets. However, you have not enabled the setting.

I understand that other mail servers you may have used do not require this, and I also understand that many businesses do not currently conform to "standards" with regards to properly implementing SPF, DKIM and DMARC, much less implementing them at all. Regardless, that is how SmarterMail works, and there ARE workarounds if you want to implement them.

2. Regarding POP Retrieval, the issue with it stopping is one we cannot replicate. We DID replicate it in a pre-BETA Build, but have been unable to replicate it in any Build since the BETA. The other issue we found with your environment revolved around the intermediary server you're using which causes the SPF address to be mismatched against the sending domain. We've offered instructions on how to whitelist that IP address, but you have yet to add it to the whitelist. If you do, and enable Bypass Spam Checks for that IP, it should work around that issue. 

Thanks for responding Derek.  I had reviewed his tickets and was going to post something similar. It looked like we offered a couple suggestions but he had not implemented them.