From Kevin at WCG
World Community Grid has never supported the anonymous platform mechanism. However, because of two bugs, one in the client and one in the server,

volunteers were able to fetch work using the anonymous platform at WCG.

The bug that is fixed in the BOINC client is that before 7.0.40, if you were using the app_info.xml file & your client supported an 'alt-platform', then the client would send 'anonymous' as the primary platform but also report an 'alt-platform' (which it should not have been sent).

The issue on the server side is as follows. When the server receives a request, it adds the primary platform and any alt-platforms that the project supports to an 'allowed platform' list. If the first platform on the allowed platform list is the anonymous platform, then the server code handles the request using the anonymous platform code path. If the list size is 0 then a message is reported back to the client that the platforms reported are not supported.

The server bug is that if the primary platform is the anonymous platform, then any alt-platforms should not be considered. Instead, the server code added the alt-platforms to the list anyway.

This is an issue for us because since we do not support the anonymous platform, that is discarded during processing and not added to the allowed platform list. However, the alt-platforms are added to the list. Since the list size is > 0, processing continues down the normal server side logic. It is this that caused the generation of the 'ignored app version' message. It also meant that if I user only specified hcc1 in their app_info.xml file, but they had opted into receiving work for more than hcc1, then they would be assigned work from those other projects and the client would immediately discard that work (and not report that fact to the server).

After discussing with BOINC, the decision was that volunteers should be able to have fine grain control over how many instances of a job are run on their GPU and that the anonymous platform mechanism is not the way that should be done. The decision was made to create the app_config.xml file so that volunteers could have control over this by making changes to the file which has been added in the 7.0.40 client. Volunteers at World Community Grid should be looking as this is stabilized as the way to run multiple copies of HCC1 GPU on your graphics card at one time.

Once the changes for the app_config.xml file are in a stable BOINC client release, we will disable the anonymous platform on the server side. We will provide warning in this forum before we do that and we will allow time for volunteers to upgrade to the stable client build before we disable the feature.
Discussion here.

The 7.0.40 was buggy and they are up to version 7.0.42 the last time I checked.