Can I modify the text in the notifications e-mails?

E-mail Notifications & SMTP
Yes, all the email templates can be modified and they are located under administrator menu - Settings - Notifications - Email templates.

Use the procedure described in the help to replace a template at:

The following information is related to old EP versions (7.1 and below):

You can find and modify the e-mail notifications templates in the \App_Data\Notifications subfolder of the EP.NET installation folder.

It's best to test 1 or 2, first, instead of changing all of them at once.

But, before you change anything make sure to make a backup copy of the originals, first, in case you need them.