To revert a database back you need to do a
load ncompact -R fullpath.nsf
This will revert the ODS back one, so if you are on 8 it converts it to ODS 43 .
You can also create a replica of a database and use the database.ns7 name which will limit the database to Notes 7 ODS,
this allows databases to remain at a Notes 7 accessible design.
ODS stands for On Disk Structure.
ODS 20 Lotus Notes 4 - NB 4Gb maximum database size.
ODS 41 Lotus Notes 5 .NS5 .NT5
ODS 43 Lotus Notes 6.0 .NS6 .NT6 NB Max database size is 64GB or maximum allowed by host OS.
ODS 43 Lotus Notes 7.02 .NS7 .NT7
ODS 48 Lotus Notes 8.1 .NS8 .NT8