Summary: A solution for "pear/pecl is using a unsupported protocal (protocol)".
While trying to install the APC Opcode Cache on a server yesterday, when I tried to run this command:
pecl install apc
I kept getting this error message:
pecl.php.net is using a unsupported protocal - This should never happen. install failed
After doing some research, it looks like you can also get a similar error message with PEAR:
pear.php.net is using a unsupported protocal
The solution I found was on this PEAR forum page. Apparently there was a problem in the PHP 5.2.10 release, and the ".channels" directory in the PHP distribution is not correct.
To solve my problem, I did what the person wrote at the end of that page:
After running the update-channels command, I confirmed that the directory was created, and the files in that directory looked much better. After that I was able to run my PECL command just fine.