Hello JimboJoe,
Quickly I’ve apply this command on my Raspberry Pi : sudo yunohost app upgrade roundcube -u https://github.com/YunoHost-Apps/roundcube_ynh/tree/testing --debug
The problem is always there 
The send button is inactive and the save button seems to be a little active because the circle turning at the bottom of the web page but don’t do anything else.
ppr