Hi,

I’ve been testing a set of apps that use the InterBase 7.5.1 client library against Firebird 3.0.2 and have found them to be sufficiently compatible (with minimal changes).  However after updating a server to Firebird 3.0.3, InterBase 7.5.1 clients (including isql) hang when executing a simple SELECT query.

I understand that this is not explicitly supported, but wonder if it was intended that this update would break the existing de-facto compatibility.

Wireshark traces show that the server is sending all the data from the query, but the client is not recognising it and waits forever – I can provide more detailed examples, logs etc if anyone is interested.

Background: I’m planning to upgrade a point-of-sales network of ~1000 lanes from InterBase 7.5.1 to Firebird 3.  Since each lane has a local db, and there are multiple apps that connect to lane and central dbs, I want to ensure the apps can work before and after migration, so as to avoid having to update everything all at once.  I originally planned to leave the clients on gds32.dll from InterBase 7.5.1 until after all databases had been migrated to Firebird, then update the clients too.  It seems another possibility could be to update the clients first to fbclient.dll from an older version of Firebird (FB2.5.7 seems to connect to IB7.5.1 ok) before migrating the databases.

Cheers,

Steve