Briefly: In version 2.23 the compilation and packaging of Gwyddion for MS Windows has substantially changed. So while it is the same program the upgrade from a pre-2.23 version to 2.23 or later requires some care.
The main changes are as follows:
The only recommended upgrade method is following:
The new installer does no try to detect and replace pre-2.23 versions of Gwyddion.
The new Gwyddion installer includes Gtk+ runtime for easier single-step installation. Do not install the separate Gtk+ runtime package unless you have other programs that use it; Gwyddion will use the bundled version even if you install it.
To downgrade to a pre-2.23 version, you also should remove the new version and then install the old version afresh.
The layout of the installation directory is the same as on Unix systems now.
This is only important if you put custom modules or data into the Gwyddion
installation directory (as opposed to gwyddion directory in your Documents and
Settings which has not changed). Modules are in
lib\gwyddion\modules now and data are in
Third-party extensions might work only with pre-2.23 versions or only with version 2.23+. The authors of the extensions should specify which Gwyddion versions it works with.
We do not have the expertise to fix them. If you have or know more about the probable root cause please help.
The official Win32 executables are cross-compiled using Fedora MinGW32 cross-compilaton environment. The procedure is described in the user guide. It is suggested that you use this method to compile Gwyddion or extensions. The sample external module threshold-example supports this method since version 2.1.
However, we are also interested in reports of native MinGW32 compilation (i.e. under MS Windows) and cross-compilation in other distributions, both successful and unsuccessful, as they should work too.