There are lots of coming changes in evolution related to security stuff (not only) so I request version bump to latest release: https://github.com/GNOME/evolution/releases The ebuild is available at zugaina: https://data.gpo.zugaina.org/gnome-next/mail-client/evolution/
3.29.1 is a VERY early development cycle release, with stable release coming our in September. So, no, we will not bump to 3.29.1, we are busy with getting to 3.26 and 3.28. It would be package.masked anyhow; if all goes well, might see 3.29.90 or such in August-September p.masked realistically. But again, my point is, 3.29.1 is a development release that mostly only people that report bugs and provide patches should be looking at.
Ah, ok I see. I am in general looking for some version which supports OAuth2, so I can configure my gmail account not allowing less secure application which at moment I must allow with current stable version. But I understand your point of view, ok lets wait for September, summer is here anyway, so ... :-) I am closing it.
evolution supports gmail via OAuth2 since long ago. Including the outdated 3.24 versions currently in main tree. This is done via evolution-data-server USE=gnome-online-accounts OR USE=google. USE=gnome-online-accounts offloads it to gnome-online-accounts (which other GNOME things use as well, to get oauth to google for other services than mail as well at the same time, with fine-grained permissions towards each in gnome-online-accounts account settings). USE=google is its own implementation, in case you don't want to use gnome-online-accounts. I believe in the former case (gnome-online-accounts) the account will just automatically appear in evolution if configured in gnome-online-accounts (via gnome-control-center[gnome-online-accounts] provided online accounts panel) and e-mail access is allowed. And I think in the latter case (USE=google) you can get it used by just adding a new mailbox and letting evolution figure out the details, but I haven't tried that personally. I use it (as a full GNOME user anyways) via gnome-online-accounts, and I've never configured my gmail separately in evolution, it just came from online accounts and Oauth2 from there.
The USE flags aren't mutually exclusive, you can have gnome-online-accounts support, but still enable USE=google as well. Both will enable the backend code for google-auth, and then one will also enable GOA integration, the other its own Oauth2 code with webkit-gtk dependency to show the google login stuff; what is used at runtime depends how you add the account (in GOA settings panel or inside evolution). gnome-online-accounts way will provide access to calendar, contacts and tasks as well; USE=google way might too, but I'm not sure if it really does and how (as I don't use that way myself and haven't checked into that part).
Oh, and I'm not sure if it's Oauth2 or what. I think google does something custom as well to need separate additional support code...