Simconnect version 4.5 does not work with 4.1

[vt79]

I have p3d v4 professional (v4.1.7.22841) installed on my windows 10 box
I wrote a sample C++ application using Visual Studio 2019 that connects to simconnect (SimConnect_Open) and waits for the SIMCONNECT_RECV_ID_OPEN message to come back so I can print out the version of P3d using the received data. My application is a x64 application using 2019 build toolset (142) and I'm using the p3d v4 sdk from https://www.prepar3d.com/support/sdk/

When I run my program, it connects to simconnect just fine but I get 2 messages back, one with SIMCONNECT_RECV_ID_EXCEPTION and the exception is SIMCONNECT_EXCEPTION_VERSION_MISMATCH and following that another one with SIMCONNECT_RECV_ID_QUIT

If I run my program on a Windows 10 box with p3d v4 (v4.5.13.32097), it works fine and I get the SIMCONNECT_RECV_ID_OPEN message

If I run my program on a Windows 10 box with p3d v5, it works fine as well

I thought the p3d v4 sdk would work with all p3d v4 versions. Isn't that true?

I would like my program to work with p3d v4 and v5 and preferably use VS2019

What do you recommend?

[BenBaron]

Hi,

nope...you cannot run a newer SimConnect client with an older SimConnect Server (which is basically the P3D version). As you might make requests that are simply not supported by the server and would lead to unexpected behaviour.

The other way around works, though: comile against an older client and you should be able to connect to the following servers.

Greets,
Ben

[hso]

As BenBaron said, only the server provides backwards compatibility for clients, not the other way round.

If you want to maximise compatibility, you'll want to use the oldest SimConnect library you can bear (i.e. one which still contains all the necessary functions for you). The oldest one that works with P3Dv4 is FSX SP2, but I haven't tested it with v5 yet.