RIP Roundcube, farewell my friend. So, what should we expect now? To have RC as NextCloud's default e-mail interface OR to get RC filled with mindless bugs and crappy features/decisions? Read this to see how bad NC's Webmail is: https://lemmy.world/comment/5490189
Also, what about Kolab https://kolab.org / https://kolabnow.com? Besides providing e-mail hosting they seem to be the ones pushing the development of RC and essential plugins that are somehow competition for NextCloud.