Hey @Jino, yes that true that they stopped Selenium IDE and the newer version of firefox doesn't support it.
I have worked with Katalon Studio and found it as good replacement for Selenium IDE.
It is free and also works on multiple platforms.
Selenium IDE was a great hit when it was first introduced but then by the begining of this year when Mozilla shutdown the add-on platform it was pretty sure that Selenium IDE is not going to be there.
Talking about Katalon studio:
Its easy to use just unzip the package and you are good to go.
The log recording capability of Katalon is powerful as compared to Selenium IDE.
Reporting and Integration are easier on Katalon.