Can I know both version numbers you had played and downloaded?(better if i can know the both websites where you downloaded) I will try test it out. And the file type of your save file too.
If I have to say blindly, you should try open in old VBA again and saved it with both in-game "SAVE" or "Ctrl+S" save. And then, copy the in-game save file into "battery" folder in the directory where new version is located. If there is no such folder, create it. And, the save file saved with "Ctrl+S" will go to "save" folder. Create it too if there isn't.
After that, open the new emulator. On the menu bar, go to >Options/ Emulator/ Directories... .
Click on the "Browse" button next to the "Battery" title and locate it to where you want to put the in-game save files. For now, it will be the path where you create "battery" folder just before.
Click on the "Browse" button next to the "Save Game" title and locate it to where you want to put the "Ctrl+S" save files. Yes,for now is where you create "save" folder just before.
Like this, you should be able to load it if the versions are not too different.
Normally, you can place both save files in where the rom file is located. I just want to make it sure. If you do like what I said, you will need to transfer the saves of other games that you played with new emulator because if you don't, those games will also become no save file to load. The logic is quite simple. By doing like that, the emulator will choose the path you selected automatically as a place where to look for the save files and will also save it there automatically. If there is no corresponding file, you can't load the game.
If you want to use the link, better use the link version of 1.7.3. You can get it at
http://gcemu.dcemu.co.uk/visualboy.shtml. With that, you won't even need the wireless adapter and can be connected with network cable. or should I say I had never tried it out with the wireless adapter.
:excl:
Always remember
Whenever it comes to the save file editing or something, you should copy the save file 1st and paste it to somewhere safe because you may lose the save file or crush while working. If it does and you don't have a backup, you are doomed.
And, better not speed hack even it is possible because it will increase the chance of breaking the linking process.