[chef] How to properly upgrade chef-server from 11.08

[William Hatch < >]

I've hit a known bug with the web-ui, where the show action on a cookbook 
results in "ERROR: undefined method `close!' for nil:NilClass". On a somewhat 
related note, the same cookbooks' changes are not being picked up on a client 
when converging. Due to the error, I cannot confirm (or I don't know how) 
whether or not the knife upload is actually resulting in my changes being 
persisted on the server, although the knife command returns success. So, I'm 
thinking it might be best to upgrade the server. I've been looking for a 
definitive resource on the proper means of upgrading chef server, but not 
finding anything very concrete.

Per the /version, I've got:

chef-server 11.0.8

Component               Installed Version   Version GUID                      
            
-------------------------------------------------------------------------------------------
bookshelf               0.2.1               
git:0a01f74ffd1313c4dc9bf0d236e03a871add4e01  
chef-expander           11.0.0              
git:14b11a96da1273b362f39ab11c411470688a8bd6  
chef-gem                11.4.0             
chef-pedant             1.0.3               
git:15de6cd06f16ee5dee501d6aba36f4ba60162e62  
chef-server-cookbooks   11.0.8             
chef-server-ctl         11.0.8             
chef-server-scripts     11.0.8             
chef-server-webui       11.0.4              
git:498097c0793e51e4f4e7df9f35ee1a3ed3282841  
chef-solr               11.0.1              
git:bcd45175fd402f3082e7146f94c5d571b0620434  
erchef                  1.2.6               
git:77ade20f166367b5f0cde468e3c6066b8a327475  
nginx                   1.2.3               
md5:0a986e60826d9e3b453dbefc36bf8f6c          
postgresql              9.2.4               
md5:6ee5bb53b97da7c6ad9cb0825d3300dd          
preparation             11.0.8             
rabbitmq                2.7.1               
md5:34a5f9fb6f22e6681092443fcc80324f          
runit                   2.1.1               
md5:8fa53ea8f71d88da9503f62793336bc3          
unicorn                 4.2.0              
version-manifest        11.0.8 

I'm on ubuntu 12.04

Are there any solid resources that explain this, or brief summary on steps 
involved? Pointers to good resources, or brief walk through would be much 
appreciated. Thanks.

Bill