Qlik Sense upgrade failed with Powershell error: .PSNotSupportedException: Cannot create type. Only core types are supported in this language mode.

In the install log, in ServiceDispatcher.log you may find:
 

MSI (s) (A8:D0) [16:24:26:950]: Executing op: CustomActionSchedule(Action=CA_UpgradeQSMQ,ActionType=11265,Source=BinaryData,Target=**********,CustomActionData=**********)

MSI (s) (A8:40) [16:24:26:951]: Invoking remote custom action. DLL: C:\Windows\Installer\MSIEB5C.tmp, Entrypoint: CAQuietExec

CAQuietExec:  Entering CAQuietExec in C:\Windows\Installer\MSIEB5C.tmp, version 3.11.2318.0

CAQuietExec:  "C:\Windows\system32\\WindowsPowerShell\v1.0\powershell.exe" -NoLogo -NonInteractive 

CAQuietExec:  System.Management.Automation.PSNotSupportedException: Cannot create type. Only core types are supported in this language mode.

CAQuietExec:     at System.Management.Automation.MshCommandRuntime.ThrowTerminatingError(ErrorRecord errorRecord)

CAQuietExec:  Error 0xffffffff: Command line returned an error.

CAQuietExec:  Error 0xffffffff: QuietExec Failed

CAQuietExec:  Error 0xffffffff: Failed in ExecCommon method

 

 

This means Powershell is set to Constrained Language mode and not Full Language mode

To change this setting open Windows Registry and navigate to:
HKLM\System\CurrentControlSet\Control\SESSION MANAGER

Constrained language may show as 
HKLM\System\CurrentControlSet\Control\SESSION MANAGER\Environment__PSLockdownPolicy = 4

The setting for full language is '8'

Change the value from 
HKLM\System\CurrentControlSet\Control\SESSION MANAGER\Environment__PSLockdownPolicy = 4
to
HKLM\System\CurrentControlSet\Control\SESSION MANAGER\Environment__PSLockdownPolicy = 8