In my last blog post on named properties, I detailed the history of named properties, how they are arranged, mapped, and how Exchange (since Exchange 2000) has created named property mappings for x...
Updated Jul 01, 2019
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Another thing to consider is that even for existing well written MAPI clients, it seems like it is generally the sender who will be calling GetIdsFromNames() when the message is generated. The sender may then be sending to a recipeint on a different store, and the property will be dropped. For Exchange 2010, if I understand correctly, the map is moving to a per mailbox model, and the every user will have to essentially send one message that may or may not properly display x-headers on IMAP clients of the recipient, so that when they themselves eventually receive a message with x-headers it will display.
This is going to look like very flaky and erratic behavior to any end user.
I think all of this argues for my scenario in my first post above to continue to work as it does in RU8, or at least allow admins the option of allowing it to continue to work this way. It achieves the goal of culling from the named property mapping table most of the x-headers that just sort of float into the org from the internet, while allowing MAPI clients and foreign gateways to still function.
I'll stop spamming now :)
This is going to look like very flaky and erratic behavior to any end user.
I think all of this argues for my scenario in my first post above to continue to work as it does in RU8, or at least allow admins the option of allowing it to continue to work this way. It achieves the goal of culling from the named property mapping table most of the x-headers that just sort of float into the org from the internet, while allowing MAPI clients and foreign gateways to still function.
I'll stop spamming now :)