http://www.icyphoenix.com/viewtopic.php?f=27&t=2140&p=22092#p22092
-----------------------------------
novice programmer
Mon 10 Dec, 2007 15:53

Re: 1.1.0.15a - Cumulative Patch
-----------------------------------
[quote user="Hip_T" post="22088"]Sorry,
I don't update my forum from a lot of time.
I've the version 1.1.0.15.
Can I update directly to "Icy Phoenix 1.1.0.15d or 1.1.7.22a RC1" or i've to do all the update (a,b,c,d,RC1)?
Thanks.[/quote]

I think you should upload all files from a 1.1.0.15d fresh install without rewriting the config.php file.
Not upload the install folder.
Not sql queries needed.