You should not use an outdated version of Electrum. You will have problems sending and fee estimates will be too low. Newest is 2.8.3 at Electrum.org. Electrum explains how to use two computers (one always offline) for cold storage here. Almost no one bothers with this setup anymore since hardware wallets are more secure and inexpensive. Get a hardware wallet.I agree. These are your best bet to guard against any attack you don't want. Having hardware wallets don't share what they have inside. So even if you use them on a virus infested computer you have, it will still store your coins safely.
Usually when you use electrum for a cold wallet you don't actually use it as a wallet, you use it to store the wallet's seed and private keys, you can later load the wallet on a newly version of electrum.
The reason you shouldn't use elctrum is that below version 3.1 there is a flow that may result you to lose your funds once you want to spend it, there is still no risk if you just use electrum for storing the private keys and not for redeeming the outputs later.