The latest products are from the Third (A)ATSR Reprocessing, conducted in 2013. This introduced some key improvements:
Evaluation and quality reports, as well as auxiliary information, from the Third Reprocessing are contained within the Third Reprocessing Information Pack
ATSR-1 Technical Documents
The following documentation is available for the Envisat-format Level 1 and Level 2 products:
The following documentation is available for the SST L2P/L3U products:
ATSR-1 Product Availability
Information on ATSR-1 products and how to access them is given in the Product Availability section.
ATSR-1 Fourth Reprocessing - in planning
Planning for the 4th reprocessing of (A)ATSR data is under way. The main focus is to harmonise the product format with that from SLSTR. More information is available here.