Sanger DAS sources respond to DAS 1.6
If a client has the X-DAS-Version set to DAS/1.6E in the request header the Sanger DAS sources at http://das.sanger.ac.uk/das/sources will respond with 1.6 style XML responses. If no header is set for this or it does not contain the number 6 the DAS 1.53E xml responses will be returned (with the exception of about 10 data sources that are labelled 1.6E with a property in the sources response ().
In the future I hope that more genomic DAS clients will move to support DAS 1.6 but in the meantime this is the Sanger solution to backwards compatibility issues which normally will only effect data sources with groups/parent/parts. This way we can also support the clients that do offer support for DAS 1.6.