Since UM2.0.x there are new handlers and place for store Email Notifications templates.
It was decided to transfer the modified email templates from the WP options to the template files because the size of the templates can be quite large. This is a fairly common practice that has its advantages. All templates are stored in one place and files can be easily edited.
So, when you edit the email template using the wp-admin screen Ultimate Member > Settings > Email it is saved in a folder with your theme/child-theme (e.g. "wp-content/themes/twentyseventeen/ultimate-member/email/welcome_email.php" is the path of the template "Account Welcome Email").
Important: Don't edit template files inside the plugin folder "wp-content/plugins/ultimate-member/templates/email/". You will lose these changes on UM upgrades.
Important: Please create the child theme if you do not use your own theme. Custom templates will be lost on the theme updating if they are stored in the parent theme.
The Ultimate Member plugin automatically creates needed subfolders in the theme directory but rarely this may be blocked by the server configuration. In this case you may connect the site via FTP and create needed subfolders manually. Make the "ultimate-member" folder in the theme writable.
Image - Directory permissions for the "ultimate-member" folder.
You can translate email templates if you use the multilingual plugin WPML. Translated template files are stored in subfolders.
Image - A place of email templates in the files tree.