Missing date header in alert emails

[janstalhut]

Server Info (please complete the following information):

• OS: Debian 12.9
• RMM Version (as shown in top left of web UI): 0.20.0

Installation Method:

• Standard
• Standard with --insecure flag at install
• Docker

Describe the bug
The emails sent by Tactical RMM do not contain a Date header. This causes my email client (Thunderbird) to display the date/time when the email was retrieved by Thunderbird and not when the email was sent by TRMM.

To Reproduce
Steps to reproduce the behavior:

1. Configure email notification in the Global Settings
2. When you receive an email, display the source code in your email client
3. There is no line that starts with "Date: ".

Expected behavior
The Date header should be included by TRMM when sending emails.

Additional context
It seems that different email servers handle it differently when the sender does not specify a date/time. It is possible that some add this information if it is missing. We only noticed the error after we switched our email server from Zimbra to Mailcow. The email server Zimbra apparently added the missing date header automatically, while the email server Mailcow apparently does not. I have now researched whether the email server is obliged to add this information: According to RFC 5322, however, it is a mandatory information that the email client must provide when sending, so in my opinion the error lies with Tactical RMM and not with the email server.
https://datatracker.ietf.org/doc/html/rfc5322#section-3.6.1