It should sync content type changes automatically: https://docs.developers.optimizely.com/digital-experience-platform/v1.4.0-content-graph/docs/synchronizing-from-site

As a first step, I would review the setup instructions, and make sure it's fully configured (including the Content Delivery API setup): https://docs.developers.optimizely.com/digital-experience-platform/v1.4.0-content-graph/docs/installation-and-configuration

Thanks for the reply Daniel.

I've setup as per the documentation (I had missed off the "Include" section). However, it's still not syncing newly created fields.

If I add a property to an existing Content (block) type or create a completely new one, it won't appear in the graph until I do a full sync.
I am creating/updating the block content each time.

My config is as follows:

  "Optimizely": {
    "ContentGraph": {
      "ContentVersionSyncMode": "PublishedOnly",
      "SyncReferencingContents": "true",
      "Include": {
        "ContentIds": [],
        "ContentTypes": []
      },
      "OnlySyncContentTypesInWhitelistToSchema": false,
      "GatewayAddress": "https://cg.optimizely.com",
      "AppKey": "b...W",
      "Secret": "g..B",
      "SingleKey": "H..M",
      "AllowSendingLog": "true"
    }
  }

And code in Startup.cs:

        services.ConfigureContentApiOptions(o =>
        {
            o.IncludeInternalContentRoots = true;
            o.IncludeSiteHosts = true;
            o.EnablePreviewFeatures = true;
            o.SetValidateTemplateForContentUrl(true);
        });
        services.AddContentDeliveryApi();
        services.AddContentGraph(_configuration);