Update README.md

Author: Mds92

README.md

@@ -12,3 +12,7 @@ Major changes:
 
 ![MD.BootstrapPersianDateTimePicker](https://raw.githubusercontent.com/Mds92/MD.BootstrapPersianDateTimePicker/master-bs4/src/MdPersianDateTimePicker.jpg)
 ![MD.BootstrapPersianDateTimePicker](https://raw.githubusercontent.com/Mds92/MD.BootstrapPersianDateTimePicker/master-bs4/src/MdPersianDateTimePickerModalMode.jpg)
+
+**NOTE:**
+Bootstrap 3 version `https://github.com/Mds92/MD.BootstrapPersianDateTimePicker/tree/master-bs3`
+Bootstrap 4 version `https://github.com/Mds92/MD.BootstrapPersianDateTimePicker/tree/master-bs4`