with the implemantation of "largeSummary" in Domino 9.0.1 FP8 the limit for the amount of Summary data per document has been elevated from 64k to 16MB.
To enable this feature for an existing database its ODS must be 52 or higher, and we need to run "compact -ls on <database>" at the console. The response then can be either, that large summary is now enabled, or that it already was enabled before running compact. There apparently ic no other way to tell, whether LargeSummary is enabled for a database.
Please include an additional field in the advanced database properties page showing the status of this flag