Hello , I have some Bitcoin in a portable elecron wallet which is on my pen drive . Now if I try to transfer the bitcoin to an address in Localbitcoin or any other address , it says "error: server didn't respond " . My electron version is 2.9.0 , which is quite old . Maybe this is the reason I am unable to send the bitcoin . And I am unable to upgrade it to current version . How do I upgrade ? And if I download the 4.0.3 version , it just doesn't open in my computer .
Do you have the recovery seed of your portable version? If yes then you can upgrade your wallet into new version with no issues.
https://electrum.org/#download here you can find the latest version, if you still having problem with installation just download the android format and install it into your smartphone then import the old wallet recovery seed here to get access to your funds.