Properly configured projects using SQLCipher shouldn’t experience problems using Xcode 9. However, changes in the new SDKs can cause compile time errors for misconfigured projects, e.g.
Implicit declaration of function ‘sqlite3_key’ is invalid in C99
Implicit declaration of function ‘sqlite3_rekey’ is invalid in C99
We have prepared important recommendations for SQLCipher developers on how to resolve these problems on the SQLCipher support forums: