I have an old Westell 2.4Ghz Wifi router which is using 128-bit WEP security (13 character password).
When I bought my HTC One it came with Android 4.2.2 and could not connect to my home Wifi. After rebooting, changing passwords, using 2.4GHz network freq on the phone, and trying the mystical power-down, volume-down, special-screen trick ... nothing worked. However, Verizon was kind enough to extend my data plan for free so I could download the massive 4.3 update over 4G network. Android 4.3 fixed my WEP / Wifi issue.
Early this morning (Feb 18, 2014), Android 4.4.2 was downloaded and installed on my HTC One. Guess what? No wifi connection after restarting the phone, rebooting the wifi, etc. Isn't that nice?
Android developers, I plead for your mercy. Please stop making x.x.2 releases!
And also, please fix the WEP issue in 4.4.3.