Actually the wallet I'm running does not have a SEED, I made it using private key only. So, do I need to create a seed first and then upgrade?
Or should I import the private keys again into the version 3.2.3 without creating a seed?
Do yourself a favor and create a new (HD) wallet. This will make backups, further imports/exports, recoveries and handling MUCH easier.
However, this means that you need to send a transaction to the new wallet and that your old addresses won't be under control of your new wallet anymore (still keeping a backup).
I'd suggest you do the following:
- Backup your wallet file and rename it to something like 'backup-2018-10-24'
- Download and install the latest version of electrum
- Open the new version and create a new wallet. Backup the new seed (non-digital, e.g. on a piece of paper, do NOT copy&paste it), and read everything carefully.
- Now copy (not move) your backup into the electrum wallet directory: press WIN-key and R, then enter %appdata%\Electrum\wallets, copy your backup into this directory
- Inside of electrum, press: File -> Open
- Choose your backup wallet. You should have 2 instances of electrum open now. One with your new wallet and one with your old wallet
- Make sure you have a backup of your new seed! Do not proceed further without having a proper (non-digital) backup.
- Now get a new address from your new wallet via the 'receive'-tab, copy it
- Create a new transaction from your old wallet to your new one, using the full amount.
- Double check everything.
You will still be able to receive BTC to your old addresses, you can simply access them by using the old wallet file in electrum's wallet directory.
A full transition to your new wallet is still desirable.