The first version is compatible with PowerShell 6:
# Solution 1 (PowerShell 6) Get-Content -Path D:\mytest.zip -Encoding Byte
The second version is compatible with PowerShell 7:
# Solution 2 (PowerShell 7) Get-Content D:\mytest.zip -AsByteStream
However for a version that works equally well between both, simply invoke the beautiful power of C# and do away with the hassle!
# Solution 3 - Use C# (PowerShell 6/7 Compatible) [System.IO.File]::ReadAllBytes("D:\mytest.zip")