Originally Posted by
vbjd1111
Hmm, that's not quite what the Delta site says. It reads: "Medallion Members are eligible for and rewarded with Unlimited Complimentary Upgrades to Delta Comfort+ and First Class on all routes where the products are available." No mention of "upgrade inventory" needing to be available. Do you have some confirmation for that restriction? Thanks for any clarification you can give.
It's well known that upgrade inventory is required, although often this is no restriction for domestic C+ "upgrades."