Has your web host sent you a mail saying your Joomla version is out of date yet? If your version is older than Joomla 3x and its a good hosting company, you will see it is their requirement now that you bring your website to the latest version. The main reason is that the older versions are not supported with updates and has become a huge security risk for most sharing environment servers.
As the internet evolves it is required for world class software such as Joomla to stay on par with accessing all the newest features that server software offer as well as the added security features that is coupled to that. Each Joomla version has a development life span. This does not mean your old website will just stop working, it only means that developers will no longer focus in maintaining those versions and writing new functionalities for it. Eventually however you will be required to migrate after having your site for at least a few years.
Please note that most third party plugins, components and modules are not Joomla 1.5 or Joomla 2.5x compatible and we need to redo those parts of the old sites using newer improved scripts. An accurate web design quote can be done upon current site inspection. If you have a small site, it would be best to convert the site to WordPress rather so you will never have to a migration again as it is an evolutionary framework and has no lifespan compared to Joomla witch is a revolutionary CMS that usually has a 4 year lifespan. Have a look at our WordPress Web Design offering. For larger websites with hundreds or thousands of articles we can also a Joomla to WordPress conversion.
Upgrade or Migrate Joomla 1.5 to Joomla 3 x
Upgrade or Migrate Joomla 2.5 to Joomla 3 x