Usually I go to the following link to find historical Genbank genome assemblies:
ftp://ftp.ncbi.nlm.nih.gov/genomes/genbank/vertebrate_mammalian/Homo_sapiens/all_assembly_versions/ to find historical Genbank genome assemblies.
However currently there is just a README file that states "all_assembly_versions & latest_assembly_versions are not listed for any species with more than 1,000 assemblies. Use the assembly_summary.txt file in the species directory to find assemblies of interest and then access the data using the ftp_path from column #20 of the file."
I follow the instructions and go to assembly_summary_historical.txt file but find that for all of the GRCh37 versions, the field says "na" for the column "ftp_path" (column #20).
Do the historical data no longer exist? Am I missing something?