Upgrade Instructions
For version 1.10.20 or higher, the upgrading process requires you to remove the existing CrossTrade NT8 Add-On DLL file from your NinjaScript Assembly. This is very simple, let's walk through the process.
Download CrossTrade NT8 Add-On Latest release — NinjaTrader 8 NinjaScript (.zip)Step 1: Close any active CrossTrade NT8 Add-On windows

Step 2: Go to Tools > Remove NinjaScript Assembly

Click on the CrossTrade Add-On and then Remove

Step 3: Import New Version
Go to Tools > Import > NinjaScript Add-On

Yes -> Yes -> OK

Final Step: Restart NinjaTrader
After restarting, you'll be good to go on the latest version!