Red Hat Enterprise Linux

Many folks have Red Hat Enterprise Linux (RHEL) or the near-clone CentOS installed on servers. Understandably, they may wish to install Statusnet on them!

PHP
StatusNet as of 0.9.0 requires PHP 5.2.4 or later, but older RHEL/CentOS releases may have an older version of PHP. Packages to upgrade PHP are pretty commonly available. (Todo: link to such info.)

PCRE library
RHEL and CentOS 5.4 and lower are known to ship with a version of the PCRE regular expression library with Unicode property support disabled. This causes a number of things to break, most noticeably failed linking and mysterious asterisks appearing in place of the letters 'c', 'p', and 's' in RSS feeds.

StatusNet 0.9.1 and later will detect this condition at installation time and refuse to continue until it's fixed to prevent this sort of data corruption.

To fix you can do one of three things:
 * If a fixed RHEL/CentOS release exists, upgrade to it. (CentOS 5.4 is known bad.)
 * Install an updated package on your older OS. Details and a sample .rpm are available from this blog post
 * Manually recompile PCRE with --enable-unicode-properties