+* Compatibility with older documents/layouts
+
+LyX 2.0.x uses an external python script, lyx2lyx, to import documents
+written using previous versions of LyX. All versions of LyX as far back as
+0.10 are supported.
+
+Of course, this means that you must have python (>= 2.3.4, <3)
+installed in order to use LyX 2.0.x with your old documents.
+
+lyx2lyx also has the framework in place to be able to convert documents to an
+earlier format (which requires python 2.3.4 at least). However, these
+converters have only been written for the conversion from 2.0.x to 1.6.x,
+1.5.x, 1.4.x and 1.3.x, so versions of LyX older than 1.3.0 will NOT be able to
+read documents saved with LyX 2.0.x. The conversion from 2.0.x to 1.6.x-1.3.x
+is lossless as long as no new features are used. lyx2lyx tries hard to find
+something equivalent for new features such as boxes, but this is known to fail
+sometimes. LyX 1.6.9 contains an updated lyx2lyx that can read documents in
+2.0.x format.
+
+Furthermore, LyX uses a converter layout2layout.py, also written in python
+that will convert old layout files on the fly. You can also call it manually
+on your layout files if you want to convert them to 2.0.x format permanently.
+
+* Formatted references
+
+Before version 2.0, LyX used the LaTeX package "prettyref" to produce
+"formatted references", such as "Section 2.1". This package has several
+shortcomings when used in a non-English environment, not least of which is
+that it has no mechanism for internationalization. (See bug #6421 and those
+it references.)
+
+As of LyX 2.0, users can choose whether to use prettyref or, alternatively,
+the "refstyle" package. The current version of refstyle, v0.5, ships with
+translations for several languages and provides an easy mechanism for users
+to translate the references it produces into still other languages. It also
+defines many more commands than prettyref does, including, for example, ones
+to produce "ranges", such as "Sections 2.1 to 2.3". Some LyX developers are
+already working with the refstyle maintainer, Danie Els, to make it work more
+easily with LyX and to extend the translations it provides. (You are invited
+to contribute translations, too!)
+
+Because many LyX users already have customized prettyref for their purposes,
+LyX 1.6.x files opened in LyX 2.0 will continue to use prettref by default.
+New LyX 2.0 files will use refstyle by default. Both can of course be changed
+in Document>Settings. Please be advised, however, that prettyref support is to
+be considered deprecated: It may well be removed in LyX 2.1, and all users are
+encouraged to adapt their layout files, etc, to refstyle.
+
+Doing so is fairly simple. With prettyref, one has declarations such as:
+ \newrefformat{for}(Formula \ref{#1}}
+The refstyle equivalent is:
+ \newref{for}{refcmd={Formula \ref{#1}}}
+The translation is obviously trivial.
+
+* Preparing for Unicode:
+
+As of version 1.5.0, LyX uses Unicode internally. This is a major change that
+affects documents and layouts likewise. We have tried to do out best to make the
+transition as smooth as possible for you. However, there are some caveats: