We are happy to inform you that we now provide a 64-bit version of T3CP, which is able to support the 64-bit versions of the SAP GUI and the SAP .Net Connector. 
The new version can be downloaded here: https://download.csbg.biz/t3cp/t3cpsetup700_x64.zip

Things to note:
The former default datasource provider is not available for x64. 
The following redistributable needs to be installed, it provides the new default provider:
Microsoft Access Database Engine 2016 Redistributable x64 (https://www.microsoft.com/en-us/download/details.aspx?id=54920)

The Access redistributable may require you to install a VC++ x64 redistributable version 14 or higher if it isn’t installed already. If an error shows up during installation, please install the latest version of VC++ redistributable (https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist).

On a fresh install of the 64-bit version of T3CP, it will automatically use the new default provider.
If it is installed over a 32-bit version of T3CP, the old provider is still part of the existing connection strings. On the first start after installing, it will show a message that the provider cannot be found and that the database is not available. The options window opens, change the “Provider=Microsoft.Jet.OLEDB.4.0” to “Provider=Microsoft.ACE.OLEDB.12.0” for the displayed connection string. After saving, T3CP should work properly. Please check existing links and update the used providers accordingly.