FortiClient 6.4 Deployment Packages - No 64-bit?

Hi there, first time poster here...! Currently running FortiClient EMS server version 6.2.4 build 0894 on Windows Server 2016.

I'm having issues with various Windows 10 machines running 6.2.7 (latest release) having a stable connection to EMS; it's like the machines will enroll and register, and then fall off again the next day/several hours later (only specific machines, at this point...). I believe this is a known issue with this particular version.

I'd like to upgrade my users to the latest release (6.4) to troubleshoot this, but when I create a deployment package for this release, I only see a 32-bit option - this doesn't apply to our machines' OS.

Please help?