The latest version works fine, the ebuild just requires some minor changes: SRC_URI="https://github.com/${PN}/${PN}/archive/imapsync-${PV}.tar.gz -> ${P}.tar.gz" S="${WORKDIR}/imapsync-${P}"
It's maintainer-needed, maybe you could open a PR for it?
Latest version is 2.229, see https://imapsync.lamiral.info/ChangeLog and https://github.com/imapsync/imapsync/tags
Created attachment 871484 [details, diff] imapsync-2.229.ebuild.patch Attached a patch for creating imapsync-2.229.ebuild from imapsync-1.977.ebuild