sendKeys not working for Android 7.0 and above

Issues/Bugs
1

sendKeys not working for Android 7.0 and above but tap is working fine

Following code is working for Android 6.0 but not for 7.0 and above.

AppiumDriver mobileDriver;

public BookingIdentificationPage(){}

public BookingIdentificationPage(AppiumDriver<AndroidElement> driver)
{
    PageFactory.initElements(new AppiumFieldDecorator(Base.driver), this);
    mobileDriver = Base.driver;
}

@AndroidFindBy(id=“et_f_name”)
public AndroidElement fName_txt;

public void enterFirstName(String fn){
fName_txt.sendKeys(fn);
mobileDriver.hideKeyboard();
}