How to print only year (no day/month) with Biblatex

In analogy to Disable month in biblatex bibliography? you can just disable the month and day fields with the commands

\AtEveryBibitem{\clearfield{month}}
\AtEveryBibitem{\clearfield{day}}

For a short moment there came to my mind that there could be a caveat with the urldate field that declares when a URL has been checked, but biblatex even takes care of this. The urldate is still printed as full date. Compare the MWE and its output below:

\begin{filecontents}{test.bib}
@BOOK{test,
author= {A. Author},
title = {A Title for a Book},
date = {2012-10-08}
},
@ONLINE{test2,
author = {A. Author},
title = {Some title},
url = {http://example.com},
urldate = {2013-01-08}
}
\end{filecontents}

\documentclass{article}
\usepackage{biblatex}
\addbibresource{test.bib}

\AtEveryBibitem{\clearfield{month}}
\AtEveryBibitem{\clearfield{day}}

\begin{document}
\nocite{*}

\printbibliography
\end{document}

Is this what you intend to do? If not, please provide a MWE to work with.

The question and answer @benedikt-bauer linked to has since been updated with a new answer which contains a nicer solution:

https://tex.stackexchange.com/a/346281/181287

The biblatex package option date=year should also work.

One may also need labeldate=year as well; or alldates=year and then something like urldate=short

Which should be valid for biblatex version 2.8 (2013) and higher.

---

Updates: For clarity, here are the relevant (shortened) parts of the manual:

date=year,short,long,terse,comp,ymd,iso default:comp
This option controls the basic format of printed date specifications.

<datetype>date=year,short,long,terse,comp,ymd,iso default:comp
Similar to thedateoption but controls the format of the <datetype>date field in the datamodel.

alldates=year,short,long,terse,comp,iso
Sets the option for all dates in the datamodel to the same value. The date fields in the default data model are date, origdate, eventdate and urldate.

Full manual with more details and explanations of the possible options can be found here: http://mirrors.ctan.org/macros/latex/contrib/biblatex/doc/biblatex.pdf