How do I upgrade my existing LyX system to version 1.3.0?
---------------------------------------------------------

If you upgrade from version 1.1.6 or 1.1.5, you shouldn't have any
problems. It is nevertheless a good idea to advise all users to run
Edit->Reconfigure.

If you have your own layout files, you may need to update them a little:

- all layout files should have a "DefaultStyle" entry

- the "Latex" font style does not exist anymore. If you really need
  its functionality, consider using the "PassThru" keyword instead.

The new layout format keywords are described in the Customization
manual.

If you have your own binding files (especially math.bind), you will
have to update them

- math-insert now takes a latex macro name as argument, so that
  "math-insert sqrt" should now be "\math-insert \sqrt"

- math-greek-toggle is now gone, and should be replaced by explicit
  bindings like

  \bind "M-m g a"      "math-insert \alpha"


Build requirements
------------------

LyX's graphics handling system has changed substantially. If you
do not have the JPEG library installed, you may need to install
it before you can use the graphics capabilities of LyX. If you
do not have the ImageMagick command-line tools installed, you
will need to modify the default set up of LyX, or install them,
in order to get previews of your document's graphics.

Document transfer
-----------------

LyX 1.3.0 uses an external python script, lyx2lyx, to import documents
written using previous versions of LyX. All versions of LyX as far back as
0.12 are supported, so any klyx users still holding out for an alternative
to xforms will finally be able to put their dinosaur to rest ;-)

Of course, this means that you must have python installed in order to
use LyX 1.3.0 with your old documents.

lyx2lyx also has the framework in place to be able to convert documents
to an earlier format. However, these converters have not yet been written
so older versions of LyX will NOT be able to read documents saved with
LyX 1.3.0.

If you were previously using the floatflt paragraph option to
wrap text around a figure, you will need to modify this for LyX 1.2.0
manually, as described in the manuals. Please ask on the lyx-users
list for assistance if you have trouble with this.
 
Note that your document may rely on the floatflt package (for example,
you may use \floatingfigure via LaTeX commands). If your document does
not have "\usepackage{floatflt}" already in the user pre-amble, you will
need to add it.
 
The babel package is now loaded after the user-defined
preamble (because some packages really need to be loaded before
babel). If you relied, on babel being loaded before your own
definitions, you can add an extra "\usepackage{babel}" statement at
the beginning of your preamble.

http://bugzilla.lyx.org/show_bug.cgi?id=315