New and Amazon Pay linked fastag was rolled out effective 15th March. All applications post 15th march are different and deducts toll from Apay wallet directly. Fastags applied before that date are normal ICICI wallet linked fastags.
Advantage of old fastags is that they can be used for Fuel at HPCL pumps, where as new fastags can't be used. If you want new version, close the old fastag and re apply again via Amazon app
P.S: I applied on 12th March and got old version. However I am keeping it since I plan to use it for Fuel purchase in future