Hi I no longer work in genomics and need to use bioconductor. I keep getting emails when someone posts. How to deregister so that I stop getting unwanted emails/posts in my mailbox? Thanks

Depending on from where do you receive mails. If they are from the support file, you need to change your profile setting on your profile: https://support.bioconductor.org/u/edit/12199/ under Notifications to "Local messages".
If you are subscribed in the developers mailing list you need to go to https://stat.ethz.ch/mailman/listinfo/bioc-devel and add your mail to the last input box.
However, if you have a package you do not want to maintain you should get in contact with the Bioconductor team.