8.5 3 64 Bit Download [patched]: Lotus Notes Client

Since IBM no longer hosts 8.5.x files on its main Passport Advantage portal (removed after end-of-support in 2018), your options are:

You can install the 32-bit Lotus Notes 8.5.3 client on 64-bit versions of Windows 7, 8, 10, or 11. Windows uses a subsystem called (Windows-on-Windows 64-bit) to run 32-bit apps seamlessly. Official Downloads: lotus notes client 8.5 3 64 bit download

If your organization still maintains an active entitlement or support contract for Notes/Domino, your best and safest route is through HCL. Navigate to the (FlexNet). Log in with your authorized corporate credentials. Search the archive for "Lotus Notes 8.5.3". Since IBM no longer hosts 8