ViewHAR/ViewSOL GEMPACK licence messages

A few users of ViewHAR and ViewSOL have been surprised by GEMPACK licence messages like:

GEMPACK licence file: C:\GP\licen.gem
Site Limited Exe-image GEMPACK licence
Release 8.0
Licence does not expire.
Licence is NOT valid because it
is Release 8.0. You need Release 9.0 or higher.

What's going on here? Surely if you bought a permanent licence, it should work forever!

ViewHAR and ViewSOL are (mostly) free

Latest versions of the file-viewing programs ViewHAR and ViewSOL can be freely downloaded, and are included in other distributions, such as RunGTAP, RunDynam or TASTE. Generally they work fine without any GEMPACK licence. However:

Above, "large" means: not exceeding various numerical limits (these are annually revised upwards). "Current" means: a licence not too much older than the version of ViewHAR/ViewSOL you are running now.

Permanent licence for GEMPACK Release 8 works forever with Release 8 programs
but has limited functionality with Release 11 programs

For example, someone who installed GEMPACK Release 8 with a permanent licence in 2003 could indeed enjoy forever the full use of the ViewHAR.exe or ViewSOL.exe that they installed at that time. But if they use their GEMPACK Release 8 permanent licence with a ViewHAR.exe or ViewSOL.exe produced in 2013 for GEMPACK Release 11, they may get a warning licence message like that shown at the top of this page. However, they could still view (but perhaps not edit) any files using ViewHAR, and could still view smaller solution files using ViewSOL.

Additional confusing factor: several copies of ViewHAR/ViewSOL on your PC

You could have several versions of ViewHAR/ViewSOL in different folders. Viewhar.exe might be in your GEMPACK folder (normally C:\GP), or in your RunGTAP or RunDynam folders. The several copies of Viewhar.exe could be of quite different ages. To understand this license problem, you should know which copy of ViewHAR you are using. For example, RunGTAP by default uses the ViewHAR.exe in the RunGTAP folder (but you can change this).

Why this annoying GEMPACK license policy?

GEMPACK Windows programs, such as ViewHAR and ViewSOL, are constantly revised: to fix bugs, to add new features, and to cope with the ever-changing Windows operating system. We want people to use the latest versions so they have a better experience (and to reduce the number of support queries).

We try, as GEMPACK evolves, to maintain backward compatibility. Forward compatibility -- the ability of older GEMPACK programs to work with modern GEMPACK programs and files -- is more problematic. In particular, programs from GEMPACK Release 8 and earlier cannot read all HAR files produced by later GEMPACK programs (details). So confusing program behaviour is likely if you use both a full GEMPACK install from 2003, together with accessory programs (like RunGTAP) from 2013. We encourage users of GEMPACK Release 8 to upgrade.

See also
Unexpected Storage Method When Reading a Header Array File