Electrum 3.0.6 is certainly legitimate and was released to fix issue #3788. I've downloaded it and I have verified the signatures and GPG says that my tarball has a good signature signed by ThomasV. If you are sure you've downloaded the executable from
https://electrum.org/#download then you're good.
gpg --verify Electrum-3.0.6.tar.gz.asc Electrum-3.0.6.tar.gz
gpg: Signature made Saturday 03 February 2018 02:29:22 PM IST
gpg: using RSA key 2BD5824B7F9470E6
gpg: Good signature from "Thomas Voegtlin (https://electrum.org) " [ultimate]
gpg: aka "ThomasV " [ultimate]
gpg: aka "Thomas Voegtlin " [ultimate]
Here's the link to the issue that was fixed in this version:
https://github.com/spesmilo/electrum/issues/3788Link to the updated release notes (I've been on IRC and ThomasV has confirmed that he is yet to merge the commit for the release notes into the master branch):
https://github.com/spesmilo/electrum/blob/3.0.x/RELEASE-NOTES# Release 3.0.6 :
* Fix transaction parsing bug #3788
Edit: As a note Electrum will automatically connect to an Electrum server as the Electrum client depends on downloading block headers from servers to synchronize and display your wallet's transactions, but you can choose to manually connect to a server. Click on the green icon on the bottom right, uncheck 'Select server automatically' in the 'Servers' tab and then choose the one that you would want to connect to.
Also over here:
https://uasf.saltylemon.org/electrum I see that server seems to be listed on my electrum as well, but that's okay to me. Anyone could setup and run an electrumX server. It's probably just your antivirus being startled by a new connection to that server or something and it's giving you a choice to either connect or to block connections to it. Nothing big since most antiviruses do this. Also, there have been reports previously of few antiviruses detecting electrum as a trojan, that's a false-positive.
noserver4u.de 50002 (SSL) ElectrumX 1.2.1
Edit2: Link to their tweet -
https://twitter.com/ElectrumWallet/status/959715463671500800