Moved from #5409:

mb21: @klpn Any downsides when using your gist? If not, would you like to make a pull request? For context: the pdfa tempalte variable was added in 46f4238

klpn: I have not discovered any problems, but I should perhaps test with some more documents. However, the Pandoc manual explicitly states that the pdfa variable "adds to the preamble the setup necessary to generate PDF/A-1b:2005", so this should then be changed as well, if we want to always use 2a (i.e. version 2, level A conformance). When using PDF/A for documents born digital, it is best to use level A (which includes Unicode mapping and tagging) if possible, rather than B, but some older preservation guidelines still require version 1. Perhaps, the pdfa variable should be changed so that the user can choose which version of PDF/A to use (different PDF:s supported by ConTeXt)?