Electrum versions older than 3.3.4 are susceptible to phishing - https://electrum.org

Since you already executed the upgrade and you see that your coins are now gone out of your hands, it's already a loss. Even posting the transaction details won't help unless someone can able to recognize the address where your coins landed although chances are slim.

Don't know how you missed this as this information was already spread out in the entire community for a quite a long time now. Sorry for the loss.