migrate_server export versus migrate export

[Dale_Lobb]

"migrate_server" is the new paradigm for upgrading one's management server.  But, it appears as of R80.40, the migrate command still exists.

SK135172 appears to specifically decry the use of migrate_server for R80.40 to R80.40 migration, since that is not an allowed upgrade path.

So, my question is: Which command does one use if instructed by TAC to upload a management export or if one is migrating hardware platforms but staying in the same version?