TL;DR - Use FindElement(By.XPath("..")) going forward.
I'm guessing you are using C# due to the capitalization of the method names. If that is the case, here is the changelog for C#. I will copy out the relevant note from the v4.0.0a4 section. The link to various changelogs can be found from
https://www.selenium.dev/downloads/
* Added support for relative locators. To use relative locators in
.NET, take advantage of the new RelativeBy class to use with
FindElement and FindElements. This change also marks the IFindsBy*
interfaces (IFindsById, IFindsByName, etc.) as deprecated. The
presence of individual methods for finding elements by each mechanism
is an artifact of an older architecture, and with the standardization
of the locator methods in the W3C WebDriver Specification, they are
now just excess code, and will be deleted.