Currently:
[ ] if one wants to check for updates, knowing vulnerabilities exist, but not knowing if they have been fixed, logically one wants to be online, so that connection to the updates site is possible.
[] BUT , that means choosing GoOnline;
that then initiates downloading of messages. That process takes a lot of bandwidth, & is not always desireable, especially if one wants to keep the downloading offline, cf. testing, or transitioning of local folders, filters....
[ ] seek way to check for updates independently of message sync(On/OFFline);
That may be a setting, wherein on chooses to automatically check-for, and download the new version BEFORE doing any actual work