I have upgraded from 11.01.to 15.01. and than to 20.01. without any formatting nor cleaning and everything works like a charm. When I tried to upgrade with the recommended wipes, the ROM did not boot but stopped on the bootanimation. So, in my opinion, formatting or wiping is not needed.
For some reason upgrade from the previous build to the newest (15.01.) in my case does not work. I did all wipes (format system, cache and dalvik), installed new ROM and reinstalled gapps and after reboot I have only bootanimation logo... No problems with the previous build (11.01.).
I tried to update to the newest build again, this time without any wipes. Strange, but it worked without any problems. Generaly, this ROM works fast and seems reliable enough for everyday use.
I think the newest CWM for Blade I is the one prepared by KonstaT . You can find in his footnote: recovery-clockwork-184.108.40.206-blade-sideload.zip
See this post
I have installed the newest build (11.1) last night and everything seems to work fine. The speed, as for me, seems very similar to that of KonstaT's 4.2 and 4.3 ROMs.
The only problem that I have noticed so far is that I could not turn off the airplane mode from the lockscreen. The menu was there after pressing the power button but pressing it did not turn off the airplane mode. I had to unlock the phone and turn of the airplane mode using the icon in notification area. Not a big issue though.
Generaly, I thing it is a very good ROM. Thanks for the great work Zeelog! It is amazing to see KitKat working on good old Blade I. :-)
There is something definitely wrong with the newest build. I have removed not needed dictionaries from LatinIME and the bootanimation and after this it fits 180 MB system partition without problem. But I can not install apps from Google Play. Wifi stops working at times, and Google+ does not work at all as it was already mentioned. It seems it is better to stay with the previous build.
I've installed the newest build and I had the same problem with Google Play Store as someone already mentioned before (nothing could be downloaded nor installed). Fortunately, KonstaT's advice to clear the data for the Play shop helped. :-)
Otherwise, the ROM seems very good. I didn't notice any problems yet.
Is there a chance to include a new version of Google Calendar in the next build? It is much more user friendly than the one included in the current ROM. It is one of the apps that I use most often. I know I can install it from Google Play store, but it would mean I would have two very similar apps in the phone.