Steps to upgrade NSX-T from 4.0.0 to 4.1.0

You may refer below link to download the next version that you want to upgrade.

https://www.virten.net/vmware/nsx/vmware-nsx-t-release-build-numbers/

Login to NSX-T console using Admin account

System -> Under Lifecycle Management -> Click Upgrade

Select MUB file path that you have downloaded ->

Download the supported MUB file

Upload the file VMware-NSX-upgrade-bundle-4.1.0.2.0.21761719-le.mub

Click Upload

Now .MUB file is getting upload, wait for to complete upload

After Uploading extracting the bundle and verifying compatibility

Now Extracting Upgrade Bundle

Now checking Compatibility Matrix of the Upgrade Bundle

Post all validation completion 

Click on Prepare for Upgrade

Accept the License Agreement

Preparing for Upgrade

Click Run Pre Checks

Pre-Check is running

Once Pre Check complete

Click Start Upgrade

Now Upgrade has completed

Now wait for complete the Upgrade

Upgrade completed with new version NSX-T 4.1.0.2.0.21761719