My university is switch email to the MS Cloud. I received this notice (among many others):

"The [university] stopped supporting less secure email authentication protocols. This change impacts username and password authentication for IMAP and POP3 Office365 email functionality.

Basic Authentication is an outdated authentication standard that allows and poses serious security risks to the [University] community and their privacy. Any apps connecting to [University] email that do not use a technology called Modern Authentication will no longer be able to connect. Email apps compatible with Modern Authentication are listed below. "

all the listed apps are, of course, versions of outlook/office, but the notice implies that there is a method of continuing. Is "modern authentication" something that I can implement in Pegasus?

It is in the works for GMail but that is all so far. You can check with the university to see if they allow the use of an app password. This is an alternative to "modern authentication" (what you will seen referred to as OAUTH2 on this forum) but it is an option that the university may not have enabled. If they don't, I do not know of a way for you to authenticate with Pegasus Mail with the current version. A new version is in beta testing but it will only be capable of OAUTH2 with GMail.

This a long discussion about MS Office 365 in October:
https://community.pmail.com/index.php?u=/topic/11743/unable-to-receive-email-from-microsoft-office-365

Thanks, Brian. I'll see what I can figure out. I suppose this is the wave of the future for anyone who needs to work with an institutional email system. I hope it will be possible for one OAuth2 system to lead to another with less difficulty.