Should it theoretically be possible to copy the bulk of the data from an existing army list from an old spreadsheet version to the new one?  I spent hours inputting all this (a real PITFA) and hoped that copying a selection of cells from the old sheet to the new one would save me the ball-aching task of inputting it ALL again.  Basically looking at the columns with the troop types, qualities and number of bases etc.  Using the latest ODS version in Libre Office.

The data seems to copy across OK but it seems to bugger up the sheet with the drop downs for troop types getting replaced with a white blank box.  Surprise surprise most of the calculations seem to not work.  Really just trying to find a way to avoid having to input all of this again.  Having the points etc on the lists is great but I think it's not possible to break from this spreadsheet entirely as you seem to need it for the PBS numbers.

Update:  While the answer might be useful to others using Libre I decided to bin one more unreliable link in the chain and subscribe to Office 365, could never stand Libre.

If copying nad pasting from an older army builder version in Excel you need to use the Paste Values option otherwise that also gets the blank boxes drop down issue - it may be the same with Libre Office perhaps?

Yeah I think it's something like that.  Before I just decided to ditch it and use Excel I tinkered with a few things, thought it may have been down to protection etc but no.  What threw me was that copying from within the new sheet was fine, just copying from the old, as you say, likely it's the need to select a formula copy option too. 

Have you taken into account the change in the order of the columns?

Yes.  As I said, not looking at it now as I've binned Libre and gone to Excel.  Before I ditched Libre though I even tried copying a single cell from the old sheet to the new one (so that wouldn't have been affected by order changes) and got the same with the drop down replaced by a white cell.  I didn't try Nik's suggestion regarding copying the formula too which maybe needed when copying between old / new sheets.