EFBs were initially divided into a number of hardware classes and software types.[23] However, later EFBs simply were categorized as "Portable" (PEDs) or "Installed".[24] Portable can be considered to consolidate the previous Class 1 and 2 distinctions, while Installed is equivalent to Class 3. These simplifications made to reduce confusion and to harmonize with already-released EASA and ICAO guidance.