Did you know Moodle 1.9 was released over 4 years ago? If you are still using it, but dream of all the new features in Moodle 2.3, then it may be time to upgrade your site!
It's true that it's a major upgrade, and depending on how old your original version is, or how many custom modules you've added, you may run into a few issues that require solving along the way. But we are keen to help you! Start with our upgrade guide and then if you do run into any problems post in the Installation problems forum and receive expert help.
Hopefully you'll make it to Moodle 2.2 without too many hitches. If so, please share your success story (like Paul Nijbakker from Lapland in his post Upgrade 1.9.17 to 2.2.3 SUCCESS!) and inspire more Moodle admins to upgrade their 1.9 sites too!