@RogerCooper The way the XML export was being done was not sustainable. In combination we were getting a decent number of bug reports of players playing 1.8 maps that were crashing on them and there is a desire to expand and simplify the XML structure. With all that being the case, in 2.3 we have redesigned the architecture of how map XML parsing is done.
The new design introduces an intermediate step into the parsing that allows us to more easily create XML tag aliases and is bi-directional so we can read and write XML data from a single data structure. This was certainly in part inspired by the bug report you submitted: https://github.com/triplea-game/triplea/issues/7480. A surgical fix there would not be worth that much as it's unlikely for it to remain correct, hence a deeper fix where the system can just export data natively from the intermediate format that is used to also read data. This will help ensure that the read and write paths of XML stay in sync since the data structure is now unified, it is bi-directional.
With all that being said, the export functionality will hopefully be expanded, but in the meantime we now have the capability to instead of saying "1.8 maps do now work", they can now work.
There is some history behind this as previously there was a somewhat broken strategy for all maps to always work. Essentially the game bundled all previous versions of the game in itself and would launch old game versions. This was a bit of a broken strategy as there is not enough information to always know exactly which version to launch, and beyond that there were other issues. As of 1.9 we dropped this as that functionality had some major breakages where the fix really was beyond the capabilities of that design (so we dropped it and decided to do a hard-cutover of maps). Now as of 2.3, we can support changes and differences in the XML natively and with far less intrusion. The two layer approach allows for the lowest XML layer to deal with tags that might be spelled differently and unify this for the next layer. This means changes to at least the XML spelling is isolated to one layer that now has automatic testing. This implies we can make changes there, they are now isolated and no longer require manual regression testing where we verify that hundreds of maps still can be loaded, that is done automatically now. Furthermore, this opened a door for bi-directionality where no only can we read from this layer, but we can write to it as well.