I am upgrading an 11.5.1 server to 12.5.2.

I ran the sqlupgrade utility in non-upgrade mode and fixed up with issues it
threw up.

There is one remaining issue which I cannot fix.

The sqlupgrade utility say that I must set the "esp execution stacksize"
server parameter value to a min of 50000.

However when I attempt to change this on my 11.5.1 server I get the following error message.

1> sp_configure "esp execution stacksize", 50000
2> go
Msg 5846, Level 16, State 1:
Server 'BACKUP', Procedure 'sp_configure', Line 433:
Illegal value '50000' specified for configuration option 'esp execution
stacksize'. The legal values are between '-1' and '-1'.
(return status = 1)

What can I do here?
Should I proceed and try and perform the actual upgrade and will the upgrade
process deal with this?

Any suggestions would be appreciated!