I wrote on the official forum siemens and they answered in private and quoted: "solid edge didn't add subscription until st6, and it does not always work well with st4 and is not recommended." ...translating with google translate: "solid edge had not added subscriptions until st6, and it does not always work well with st4 and is not recommended. "
I also have a link from which they take instructions to create travel licenses ( appendix b ):
https://support.industrysoftware.automation.siemens.com/docs/se/st7/sesetup.pdf