Why do you want version 4.1 of snapdrive? It is not GA anymore.
We are using snapdrive 4.2.1 (which was GA a year ago) with SME 3.2 for Exchange 2003 on ontap 7.0.6 and 22.214.171.124 without any problems for more than a year now. I think you can also go to SME 5.0 with snapdrive 6.x.x for Exhange 2003 if you are using ontap 126.96.36.199.
Re: ONTAP support version of SnapDrive for Windows 4.1
Yes, you need to upgrade snapdrive and snapmanager.
You could go to highest supported version of Snapdrive/SME for your environment, but then you need to upgrade these version right after the ontap upgrade. Or you could try find a Snapdrive/SME combination that is support for both 7.0 and 7.3, but I am not sure if it exists for 7.3.