The Minecraft 1.7.9 serverlist gives an "Can't connect to server." instead of the default "1.7.5 (red cross)" with "Server Outdated!" tooltip.
Attachments: First picture is in 1.7.5, Second in 1.7.9.
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Comments 4
The issue still exists after updating x64 Java to version 7.0.550
I updated the description as the error wasn't "communication error" but can't "connect to the server".
You cannot connect with 1.7.9 to servers with 1.7.5 Derp.
Modded servers are not compatible to the 1.7.9 protocol.
Works fine with vanilla Minecraft 1.7.9 and vanilla server 1.7.4, see screenshot.
I think your 64b Java may be outdated.