Compared to already stable 2.5 it adds a patch to fix a perl warning which will become fatal in perl 5.28.
Why not stabilise 2.10 already? It is in Gentoo ebuild repo since beginning of February.
All newer versions require not yet stable perl releases. I hope to dump 2.5 as soon as 5.26 becomes stable, 2.7 is the candidate for this. biber-2.10 requires perl-5.28.
amd64 stable