OK, so it turns out that GOG does have the latest patch, but you have to use Galaxy to download it (groan). I patched the game, and here's what things look like:
The application has the Tio icon, and the version number is 1.4.1.
After that, I reverted to the 1.4 executable (which I had backed up before patching) without changing any other files, and it had the following result:
The application has the Rean icon, and the version number is 1.4. This means that the version number reported at the title screen is stored in the executable itself (instead of being pulled from a different file), which in turn means that the Tio executable isn't an old .exe that was re-uploaded by accident. It was created specifically for the 1.4.1 patch.
Note that this still doesn't guarantee that the Tio icon is a tease. Maybe Durante is a secret Tio fan who still uses her image as an icon for private development builds and has forgotten to switch to the Rean icon before uploading the latest version. Maybe some files got mixed up as he moved them around. Things happen. Still, I thought it was worth sharing.
The application has the Tio icon, and the version number is 1.4.1.
After that, I reverted to the 1.4 executable (which I had backed up before patching) without changing any other files, and it had the following result:
The application has the Rean icon, and the version number is 1.4. This means that the version number reported at the title screen is stored in the executable itself (instead of being pulled from a different file), which in turn means that the Tio executable isn't an old .exe that was re-uploaded by accident. It was created specifically for the 1.4.1 patch.
Note that this still doesn't guarantee that the Tio icon is a tease. Maybe Durante is a secret Tio fan who still uses her image as an icon for private development builds and has forgotten to switch to the Rean icon before uploading the latest version. Maybe some files got mixed up as he moved them around. Things happen. Still, I thought it was worth sharing.