Thread:Project:Support desk/Updatation of Mediawiki 1.12 to Mediawiki 1.20

Could you explain what are all the risks involved upgrading of mediawiki from 1.12 to 1.20.

Product 	Version MediaWiki 	1.12.0 PHP 	5.2.6 (apache2handler) PostgreSQL 	EnterpriseDB 9.2.1.3 on x86_64-unknown-linux-gnu, compiled by gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-52), 64-bit

If there no much risk, pls guide me how to upgrade.