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The Intel® Ethernet Server Adapter I350-T4 was discontinued and is being replaced with the new version (I350-T4V2) which have the AUX Power component changes that will result in a decrease of in-rush current during power supply start-up. Product functionality does not change. That's why you don't see any differences in the specifications.
For more information on the product change, you may refer to the Product Change Notification (PCN113232 - 01).
Hope I was able to address your concerns.