Supported TLS cert formats in EC25 cell module?

I did not find any info in the EC2x_SSL_AT_Commands.PDF on what range of cert certificates file formats are supported. I see PEM files in forum posts, but our last cell module supported the CRT files common on phones. (I can convert to PEM, but just asking first).

Are only PEM formats supported? Or are a few other formats parsed as well.

There is no requirement for the file format of the certificate, as long as it is given by the security agency.