$contributionID no longer available in Memberships offline receipts

[joanne]

In 4.2. we used the the contribution id as our receipt number in both online and off-line membership receipts.

In 4.4 $contributionID is still available to online membership receipts but is no longer available for off-line membership receipts. 

Was there a conscious decision to remove it, or did it just get lost somehow?

If there was a conscious decision to remove it what was the reason for it and are there any suggestions about what we could use to replace it?  Our tax laws require a number that uniquely identifies each tax receipt we send and contribution id was perfect for this.