Before making any upgrades, make backup yours site( files and DataBase). With that you will not lost something important
If you have custom changes of component, you can lose your changes.
Please, in that case do not make update.
If you wish update property management listing software
for Joomla, from Free to PRO.
You need simply install new version without remove old, so you not lost your properties which you added before.
If you would like any further information, please do not hesitate to contact us too.
P.S. Please do site backup 2 times per month if the more often - better!