DEX Versions explained
There have been updates to DEX over the years and with each update comes a new DEX version number. An example of a DEX version number would be 004010UCS. This is referred to as forty ten and is sometimes noted as 4010 but within the actual 894 data file it is formatted as 004010UCS.
The way DEX versions work is the retailer should notify the vendor what versions they support and then the vendor is required to use one of those. For example the retailer may say they support 4010, 5010 and 5050 then its up to the vendor to send across using one of those version. The same DEX version should be used by both trading partners within the DEX session.
The most widely supported version is 4010 which came out way back in 2000 in response to the Y2K panic. More recent versions, such as 5010 and 5050 were implemented to allow for product identifiers other than standard UPC. In version 4010, the UPC was sent in the G8304 field. With version 5010 and above. the product identifier is sent in G8306 in conjunction with the G8305 identifier.