Content-Transfer-Encoding does not appear to be enforced in requests, only in responses [1]
That said, it does appear in an example of client enrollment in the spec [2].
Testing with server http://testrfc7030.com/ does not require Content-Transfer-Encoding in the request. Test server set up with globalsign/est [3] does require the header and will fail enrollment without it.
Content-Transfer-Encoding does not appear to be enforced in requests, only in responses [1]
That said, it does appear in an example of client enrollment in the spec [2].
Testing with server http://testrfc7030.com/ does not require Content-Transfer-Encoding in the request. Test server set up with globalsign/est [3] does require the header and will fail enrollment without it.
[1] https://datatracker.ietf.org/doc/html/rfc7030 [2] https://datatracker.ietf.org/doc/html/rfc7030#appendix-A.3 [3] https://github.com/globalsign/est