It has been years since this site has been has been upgraded to Joomla 1.5.26. This version is now history and totally no support whatsoever even from the Joomla community. Even with this, there was no plan to upgrade the site as it is fully functional and serves its purpose. However, there is a necessity to upgrade as Joomla 1.5.26 is not compliant to PHP 7 which is the current version of the web host serving this site. It might be logical to look for a web host with PHP 5.X but sooner or later, the options will be nil thus it is a decision that needs to be done now or the site will become history.
Automatic upgrade software was the first choice but cost is the primary constraint thus eliminated from the list. There are open source alternatives but it does not do the job as expected. Enlisting a third party to perform the migration to Joomla 3.8 is not an option due to, as previously mentioned, cost constraints. The only alternative is to perform the upgrade manually.
How to do it is not an easy task as the site is using a custom component. The first step was to create a similar component which is suitable for Joomla 3. Using the Component Creator, a basic component was created. Then, it was just customized to suit the site requirements. The newly created component was installed and tested on Joomla 3. Now it is time move to the next step.
The second step is to compare the database tables of users, contents and categories between Joomla 1.5 and Joomla 3. There are more fields in the Joomla 3 database. Thus to be able to insert an exported Joomla 1.5 SQL file into the Joomla 3 database, missing fields were added into the exact sequence like Joomla 3. Using phpmyadmin database utility, the Joomla 1.5 SQL file was imported into the new database without any issues.
The password for the users of course will not be correct but with "Forgot Password" utility in Joomla, it could easily be recovered. The categories could be rebuild using Content -> Categories link at the back end. As the content and category IDs remain the same, the links did not change thus there will be no search engine ranking issues.