5.10.13 is installed. I go to Extensions / Manage / Update, select AcyMailing Essential (5.10.19) click Update button and it reports "Invalid Extension Update"...
Why? How can I upgrade it? I have a valid license.
Thanks

Hi,

It seems like your license is not attached to your domain.

You haven't updated your Acymailing for over a year. I'm not sure in which version the license tab was added. Please go to Acymailing->Configuration and check if the license tab is present.

If present, unlink your license, save your config and then link your license again.

When this does not resolve your issue or in case you do not have a license tab in your Configuration, please raise a support ticket here: https://www.acymailing.com/support.

Ah, thanks jvstratum. It isn't attached, which I knew about, but didn't think it would affect upgrading. I did contact support over this issue and it seems I need to fiddle around inside some tables in order to get it to link correctly. Needless to say I haven't done this yet! Maybe I should try to find out what to change and where.