In case you had not heard, Joomla 1.7 will be released on July 19, 2011. This is the first release under Joomla's new 6-month release schedule.
1. Should I update my Joomla 1.6 site to Joomla 1.7?
Absolutely you should. In fact, you must. Joomla 1.6 will reach the end of its life in August 2011, just a month away. After that, Joomla 1.6 will have no further security updates, meaning that if a security problem is discovered, it will not be addressed. And that means if your site is hacked due to a 1.6 vulnerability, you will have no recourse to fix the site, other than to move it to 1.7 anyway. You might as well move it sooner than later!
Oh, and upgrading from 1.6 to 1.7 is designed to be a very simple, one-click process.
2. Will my Joomla 1.6 site continue to run if I don't upgrade?
Yes, if you don't upgrade your site, your site will run just fine ... for now. See the security updates issue above. Extensions builders will be building to the current version of Joomla, so if you ever want to add another extension to your 1.6 site, or you want to change the template, you will find some difficulty going forward.
3. How do I upgrade from 1.6 to 1.7?
First, if you're running Joomla 1.6, make sure you are running 1.6.5. This was released in late June, and it is the only version of Joomla 1.6 which will allow moving to 1.7.
4. Are my Joomla 1.6 extensions and templates compatible in Joomla 1.7?
We have been told that all extensions that are currently 1.6 compatible should not have an issue running in Joomla 1.7. As always, you will want to test this first. We strongly recommend making a copy of your site, upgrading it to 1.7, and testing the entire site thoroughly to make sure it works correctly, including the 3rd party extensions.
Templates should also be compatible between versions.
5. What new features and functionality can I expect in Joomla 1.7?
The team of people who brought you Joomla 1.6, after working for 3 years on the project, have brought you Joomla 1.7 in just 6 months. Obviously, this release does not have as many features in it, since there was significantly less development time involved with this release.
From a site builder's perspective, there are some minor improvements, such as the ability to add a background image to the custom HTML module, the ability to specify the site name before or after the page title, and a "remove installation folder" button as part of the installation process. Don't look for big changes, like a new admin template, though.
From a developer's perspective, the changes are more significant. Joomla's framework is separated from the CMS, meaning that it's possible to build new applications with the Joomla framework. (See this Joomla Magazine article for more information.) There were also over 300 bugs squashed with this release.
6. Should I update my Joomla 1.5 site to Joomla 1.7?
As always, the answer is "it depends." However, if your Joomla 1.5 site is working well, I would not move it yet. Joomla 1.5 will be supported through April 2012. Joomla 1.8 will be released in January 2012, and it is a long-term release, meaning it will be supported for 18 months instead of 6 months.
7. If I'm building a new site, should I build it in 1.5 or 1.7?
At this point in time, you will ultimately need to move your site to Joomla 1.8 in 6 months or so, whether it's in Joomla 1.5 or in Joomla 1.7. However, the move from 1.7 to 1.8 should be less painful than the move from 1.5 to 1.7. Less pain means less cost, so from a client's perspective, building in 1.7 makes a lot of sense at this point.
If you need extensions which are still not 1.6/1.7 compatible (K2 is still in beta for 1.6 and most of the full-featured shopping carts like redSHOP, VirtueMart, and Tienda are all still for 1.5 only), you may have to build the site in 1.5 for now.