What is the differences between Selenium 3 and Selenium 4 architecture?
In the Selenium WebDriver Architecture of Selenium 4, the use of WebDriver JSON Wire Protocol has been replaced with a new protocol called the Remote Control Protocol (RCP). This protocol is based on the HTTP wire protocol and looks very similar to it.
The other major difference between Selenium 3 and Selenium 4 is that in Selenium 4, you’ll need to use different language bindings for different browsers. For example, if you’re working on a test case in Java and want to access the Google Chrome browser, you’ll use the Selenium-Webdriver Client API for Google Chrome. If you want to work with Mozilla Firefox instead, you’ll use the Selenium-Webdriver Client API for Mozilla Firefox.
Hope it helps!