"Fix a bug (ticket 4c86b126f2) that causes rows to go missing on some queries with OR clauses and IS NOT NULL operators in the WHERE clause, when the SQLITE_ENABLE_STAT3 or SQLITE_ENABLE_STAT4 compile-time options are used."
http://www.sqlite.org/releaselog/3_8_3_1.html
We don't use those compile-time options for the OS X build, so, if this is the only meaningful bug, it may be a no-op. The tests pass before and after. Still, it's probably better to update now. I've opened Issue20818 as a cherry pick request for 3.4.0.