Several ways... you can see the new code committed here:
https://sourceforge.net/p/web-erp/code/commit_browser
You can then download the various updated scripts as required
OR
You can subscribe to the list at
https://lists.sourceforge.net/lists/list...eb-erp-svn
as for every change in the code a message is sent to this list showing what the change was - you can then download the changed files as necessary.
OR
You can subscribe to the svn (Subversion Repository) using Tortoise SVN or similar (assuming you are a windows user.
There is some info at:
http://www.weberp.org/Development.html
and
http://tortoisesvn.net/
If you are using linux then most distros would have an svn client