afd25ced_File_Format_Changes_in_SQLite__cription_Of_File_Format_Change
[Version Change] 2.1.7 to 2.2.0 [Approx. Date] 2001-Dec-21
Beginning with version 2.2.0, SQLite no longer builds an index for an INTEGER PRIMARY KEY column. Instead, it uses that column as the actual B-Tree key for the main table. Version 2.2.0 and later of the library will automatically detect when it is reading a 2.1.x database and will disable the new INTEGER PRIMARY KEY feature. In other words, version 2.2.x is backwards compatible to version 2.1.x. But version 2.1.x is not forward compatible with version 2.2.x. If you try to open a 2.2.x database with an older 2.1.x library and that database contains an INTEGER PRIMARY KEY, you will likely get a coredump. If the database schema does not contain any INTEGER PRIMARY KEYs, then the version 2.1.x and version 2.2.x database files will be identical and completely interchangeable.
File Format Changes in SQLite