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This section lists features and modifications that might affect the way you have installed and used Firebird in earlier releases.

Migrating the security database from Firebird 4.0 to 5.0

To migrate the security database from Firebird 4.0 to 5.0, backup security4.fdb with gbak of Firebird 4.0 and restore it as security5.fdb with gbak of Firebird 5.0. Use gbak locally (using an embedded connection) while Firebird Server is not running.


Copying security4.fdb and renaming it to security5.fdb and upgrading the ODS with gfix option -UPGRADE will work as well, but we recommend backing up and restoring.


Changes that may affect existing SQL code:

Multi-row RETURNING behaviour

Client-side INSERT …​ SELECT, UPDATE, DELETE, MERGE and UPDATE OR INSERT queries containing the RETURNING clause may now return multiple records instead of raising error “multiple rows in singleton select” as it happened before.

These queries are now described as isc_info_sql_stmt_select during preparation, while in previous versions they were described as isc_info_sql_stmt_exec_procedure.

Singleton INSERT …​ VALUES statements, as well as positioned UPDATE and DELETE statements (i.e. the ones containing the WHERE CURRENT OF clause) preserve the existing behaviour, being described as isc_info_sql_stmt_exec_procedure. They also preserve the ability of being executed within a single protocol roundtrip to the server.

However, all these queries, if used in PSQL and the RETURNING clause is applied, are still treated as singleton.

Removal of WNET protocol

Network protocol WNET (a.k.a. Named Pipes, a.k.a. NetBEUI) previously supported on Windows platform is removed in Firebird 5.0. Those Windows users who operated with any WNET connection string (\\server\dbname or wnet://server/dbname) should switch to INET (TCP) protocol instead (connection string server:dbname, server/port:dbname, inet://server/dbname, or inet://server:port/dbname).

Removal of QLI

Command-line utility QLI is removed in Firebird 5.0, in accordance with its deprecation announcement published in the Firebird 4.0 release notes.