26B ISIR Groovy enum backward compatibility issue

We wanted to share an issue we found after 26B with Groovy configuration ISIR field enums.

With 25D, several ISIR fields moved from non-FTI to FTI fields on the ISIR. Prior-year ISIR enums would then map to the new FTI data fields for the new award year making groovy backwards and forwards compatible.

For example, using a prior enum like:
isirRecord.getField(IsirField.FPS_STUDENTAVAILABLEINCOME).get() would return the mapped FTI value for 2026-27, so Groovy scripts would not need award-year-specific logic.

After 26B, we identified an unintended change in this compatibility behavior. Prior years FPS enums return values for 2026 ISIRs but return blank for 2027 ISIRs. The new FTIMPROCESSING enums return values for 2027 ISIRs but return blank for 2026 ISIRs.  This behavior breaks the expected compatibility across ISIR processing years.