Should that not be Star trek 4 since that film series has nothing to do with the original series or the previous films?
So... instead of the current numerotation, is should have been:
The Original Series films
1.1 Star Trek: The Motion Picture (1979)
1.2 Star Trek II: The Wrath of Khan (1982)
1.3 Star Trek III: The Search for Spock (1984)
1.4 Star Trek IV: The Voyage Home (1986)
1.5 Star Trek V: The Final Frontier (1989)
1.6 Star Trek VI: The Undiscovered Country (1991)
The Next Generation films
2.1 Star Trek Generations (1994)
2.2 Star Trek: First Contact (1996)
2.3 Star Trek: Insurrection (1998)
2.4 Star Trek: Nemesis (2002)
Reboot films
3.1 Star Trek (2009)
3.2 Star Trek Into Darkness (2013)
3.3 Star Trek Beyond (2016)
3.4 Star Trek 4 (TBA)