RED Tunnel UTM <-> XG

Hi Folks,

currently iam testing with UTM and XG envs. due to that iam not able to get a RED Tunnel between UMT(s) and XG(c) to work i found that pretty old thread:
community.sophos.com/.../red-site-to-site-between-xg-and-utm

does the problem that an XG can not be the client for an UTM still exists? cause my XG is also saying "Invalid File"

Thanks in advance,
Jan