What compression format can be used to send files via gmail?

Question

gmail

Tried to send in zip and 7z and both times I get a return letter

For security reasons, Gmail does not allow you to use this type of file as it violates Google policy for executables and archives.

It used to ship just fine!
What format to send?

Answer 1

zip
gz
https://support.google.com/mail/answer/6590?hl=en

To protect you against potential viruses and harmful software, Gmail doesn't allow you to attach certain types of files, including:

• Certain file types (listed below), including their compressed form (like .gz or .bz2 files) or when found within archives (like .zip or .tgz files)
  
• Documents with malicious macros
  
• Archives whose listed file content is password protected
  
• Password protected archives whose content is an archive
  

Answer 2

Password-protect the archive, then Google will not be able to get inside and let it through.