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DAS

1.6 : the current official version of the DAS specification
1.6E : extensions proposed by the community for inclusion in a future official specification
1.53 : the previous version of the DAS specification
1.53E : extensions to the previous version, some of which are adopted in DAS 1.6

DAS/2

2.0 : The latest stable DAS/2 specification
2.1 : discussion of a future DAS/2 specification