RE: Trying to post an entry within more 2 years from our current open year
In General Ledger, transactions are classified either as open or history. When you close the year, journal entries of the current year are moved to history. In this essence, when you remove journal entries from history, you are deleting these journals.
This actually has nothing to do with posting one year prior to the first day of the earliest open year. Even if you remove history, you still can not proceed with this type of posting.
My only recommendation is to open a ticket with Microsoft to do it correctly. Setting a plan for upgrade is a must to take advantage of the various new features including the reverse year end close one.
Your feedback is highly appreciated,