Thanks for your message.
The error message ‘Record not processed because submitted version: ___ is less or equal to previously submitted version (DOI match)’ indicates that the timestamp in your deposit is numerically lower than (or equal to) the timestamp used in a previous deposit.
Every deposit has a <timestamp> value, and that value needs to be incremented each time the DOI is updated. You can find the most recent timestamp by reviewing your past deposit XML, which is created for you when using the web deposit form (and emailed to the email address you enter at the end of the form). Timestamps are also listed in the depositor reports available here: http://0-www-crossref-org.brum.beds.ac.uk/06members/51depositor.html
When we launched the new Metadata Manager tool, we automated the creation of the timestamp. Metadata Manager uses a 17-digit timestamp using the YYYYMMDDHHMiMiSSmmm format (where Y = year; M = month=; D = day; H = hour; Mi = minute; S = second; and m = millisecond). Our schema does allow for timestamps of 19 digits, so the only way of triggering a timestamp error in Metadata Manager is if a member created XML outside of Metadata Manager with a timestamp greater than (or equal to) the 17-digit timestamp autogenerated, using UTC time, by Metadata Manager and then added that record to Metadata Manager and attempted to update the existing metadata record. That’s a long way of saying very few members should ever see a timestamp error when using Metadata Manager to register or update their records.