Reply To: customs field not showing in mail because fieldname changes after

I installed the update but it looks like nothing has changed. It used to work fine and now it is a mess.
After adding a hand made customfield the one added before simply disappears!

Adding pre-installed custom fields doesn’t work either. Also the fields do not show in e-mails and the fieldname in the dashboard dissapear after saving the changes.

it looks like there is a maximum of 5 custom fields!?

Please help