First set `CXProviderConfiguration` for grouping and multiple calls, like
let providerConf = CXProviderConfiguration(localizedName: applicationName) providerConf.supportsVideo = supportsVideo providerConf.supportedHandleTypes = [.phoneNumber] providerConf.maximumCallGroups = 3 providerConf.maximumCallsPerCallGroup = 2 /// 2 calls max per call group. Excluding host call
Also, you need to set `CXCallUpdate` when receiving the incoming call to tell `CXProvider` that the incoming call can be held/un-held and grouped
let callUpdate = CXCallUpdate() callUpdate.supportsGrouping = true callUpdate.supportsUngrouping = true callUpdate.supportsHolding = true
Use that update each time you are about to report a new incoming call to `CXProvider`

You need to set to `CXProviderConfiguration` that the app allows call grouping and multiple calls, like
let configuration = CXProviderConfiguration(localizedName: applicationName) configuration.supportsVideo = supportsVideo configuration.supportedHandleTypes = [.phoneNumber] configuration.maximumCallGroups = 3 configuration.maximumCallsPerCallGroup = 2 /// 2 calls max per call group. Excluding host call
Also, you need to set `CXCallUpdate` when receiving the incoming call to tell `CXProvider` that the incoming call can be held/un-held and grouped
let callUpdate = CXCallUpdate() callUpdate.supportsGrouping = true callUpdate.supportsUngrouping = true callUpdate.supportsHolding = true
Use that update each time you are about to report a new incoming call to `CXProvider`