RPE 1.3 does not change the template language version. This means that templates created with RPE 1.3 can be used with older RPE versions and with the RRDG engines embedded in point products. If used in the template design new elements like “Document Break” will be ignored by older RPE versions and a warning will be logged.
With RPE 1.3 we have upgraded the component used to produce the Word and PDF output and fixed a number of defects and this will result in some differences between the output produced by RPE 1.3 and the output produced by older versions for the same template. In all cases we expect better and more correct output documents produced by 1.3.
With regards to RRDG 1.3 and its adoption by Rational point products at this time there are no products embedding it. You can however use RPE 1.3 to create templates for usage in RRDG and you can use the new Studio debugger from RPE 1.3 to find and correct problems with existing templates.