Useful info on schema versions:
Natty, zeitgeist 0.7.1, schema version 3 Oneiric, zeitgeist 0.8.2, schema version 4 Precise , zeitgeist 0.9.0, schema version 6
Useful info on schema versions:
Natty, zeitgeist 0.7.1, schema version 3
Oneiric, zeitgeist 0.8.2, schema version 4
Precise , zeitgeist 0.9.0, schema version 6