The downgrade process will involve downloading the version of Tools you want, then mounting the CD on the VM, and installing Tools.
The only difference is that the launch process isn’t the usual VM > Guest > Install/Upgrade VMware Tools, but rather just mounting and running the Tools installer from the .ISO image like any other piece of software.
To download tools:
If the guest OS is running on ESXi 5.5 U2 with VMware Tools 5.5 U2 and I downgrade the VMware Tools to 5.1 U1, will there be any adverse effects with running a lower version of VMware Tools on ESXi?
I just downgraded the VMware Tools on the Guest OS, Exchange 2013, and it fixed the TcpAckFrequency issue.
I have no errors in device manager when using 5.1 U1 VMware Tools on 5.5 U2 ESXi server.