Archival Nodes are clients on the Bitswift network which have enabled the archival property in the nxt.properties config file. Archival nodes store information that has been pruned from the blockchain. The default setting is to keep the pruned data for 90 days.
To edit an archival node config you must first edit the nxt-default.properties config file which is located at C:\Program Files\Ardor\conf (windows)
Set the values below
nxt.maxPrunableLifetime=7776000 (Override the lifetime of prunable data to keep them longer) nxt.includeExpiredPrunable=True (Include expired prunable parts if requested as long as it is still available)