I'm getting an error trying to use biocLite("BiocUpgrade") to go from Bioconductor 3.1 to 3.2 with R 3.2.2. It's telling me the only update option is to devel. On another machine I had been using devel and the update was seamless, BiocInstaller updated itself to 1.20.0 upon first use of biocLite().

> source("http://www.bioconductor.org/biocLite.R")
Bioconductor version 3.1 (BiocInstaller 1.18.4), ?biocLite for help
> biocLite("BiocUpgrade")
Bioconductor version 3.1 (BiocInstaller 1.18.4), ?biocLite for help
Error: Bioconductor version 3.1 can be upgraded, but only to 'devel'; see ?useDevel.
  Use biocLite() without any arguments to update installed packages
In addition: Warning message:
'BiocInstaller' update failed, using version 1.18.4
> sessionInfo()
R version 3.2.2 (2015-08-14)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Red Hat Enterprise Linux Server release 6.5 (Santiago)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
 [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] BiocInstaller_1.18.4

loaded via a namespace (and not attached):
[1] tools_3.2.2

So I think a better answer for you is that it appears that the BiocInstaller package is installed in a location where you (the user your're running R as) do not have permission to overwrite it. 

The biocLite("BiocUpgrade") command is trying to upgrade the BiocInstaller package so it is failing because of this.

So one approach would be to remove the package:

remove.packages("BiocInstaller")

You may need to be running R as root or another admin user in order for that to work.

Then as the user you normally run R as, do:

source("https://bioconductor.org/biocLite.R")

That should install the 3.2 version of BiocInstaller (in a location where it can later be auto-updated) and then you can just run

biocLite()

to upgrade all your installed packages.