It is not a new update, if there are no "DAO" interaction your witness votes expire, if I recall correctly, within 1 year. As a small witness myself, I have seen a loss of votes from smaller Hive users who voted but never updated their approvals list, so some votes ended up expiring.
If you want to approve some witnesses it is important to stay active on Hive's DPoS to prevent your votes from expiring (within 1 year). It is never bad to review your votes, add some, remove some and maybe talk to your witnesses to make sure your interests are still aligned, or maybe that they can become aligned (a democracy is all about talking)
Additionally, consider checking for new witnesses who may deserve your vote. I have been witnessing for 2, almost 3 years, so maybe I could be on your list too :)
I have not been including my Witness "plug" at the end of my posts because I wanted to maintain clean posts, but I will now include it: