5.5.4 outdated client

Development Programming & Scripting
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1

Hello,

I’ve recently started encountering this error when a client connects to the server (peer-to-peer connection using ?listen during level loading, with Steam and the Advanced Sessions plugin):

[2025.05.01-19.01.57:003][562]LogNet: Error: Server is incompatible with the local version of the game: RemoteNetworkVersion=4242879735 vs LocalNetworkVersion=689173867, RemoteNetworkFeatures=IrisReplication vs LocalNetworkFeatures=GenericReplication
[2025.05.01-19.01.57:004][562]LogNet: Error: UEngine::BroadcastNetworkFailure: FailureType = OutdatedClient, ErrorString = The match you are trying to join is running an incompatible version of the game. Please try upgrading your game version., Driver = Name:PendingNetDriver Def:GameNetDriver SteamNetDriver_3

I tried adding the following lines to the DefaultEngine.ini file, but nothing seems to work:

[SystemSettings]
net.UseIris=false

[/Script/OnlineSubsystemSteam.SteamNetDriver]
bUseIris=false

[/Script/OnlineSubsystemUtils.IpNetDriver]
bUseIris=false

I eventually reverted to a version of the project that was working perfectly two weeks ago, but after recompiling (note: the binaries are not on GitHub), the same issue came back. That version had no problems before.

Does anyone have an idea why this might be happening?

2

A few things you could try:

  1. Disable the Iris Plugin.
  2. bUseIris = false; in your .Target.cs
  3. bUseIris = false in your .Build.cs
  4. ↓
[SystemSettings]
net.Iris.UseIrisReplication=0
  1. Start your game with -UseIrisReplication=0 in the commandline.
3

The issue was actually caused by the client joining the session immediately after the search. By adding a button that the client has to click to join, everything worked fine.

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