Hi,
I have one custom theme for my company and have realized that the logo-mail.gif is not used when the system sends mails to users: the logo used is the NC defaults.
If I try with the example theme the behavior is the same.
How can I change the logo so that NC can use the one I have at my theme dir?
Nextcloud version : 17.0.0
Operating system and version: Ubuntu 18.04
Apache or nginx version: 2.4.29
PHP version: 7.2.24
Same problem here. Does anybody found a solution? 
More information here
The logo in the mail notification is linked to:
https://my.url.de/themes/mytheme/core/img/logo.png?v=fe63de357e3784c69ab4448b7e67a25c63856b1e
I replaced the logo.png with my logo.png. But the logo is still the “custom cloud” logo.
The Link https://my.url.de/themes/mytheme/core/img/logo.png shows my logo but the mail notification add a strange code “?v=fe63de357e3784c69ab4448b7e67a25c63856b1e” behind the png and this is linked to the custom cloud logo…
But a solution seems to be still missing.
I wasn’t unable to make it work… I finally used the Theme App…
