These are the six second-person passive heavy-nūn positions:
Word / formMeaning / explanation
لَتُفْعَلَنَّsecond masculine singular
لَتُفْعَلَانِّsecond masculine dual
لَتُفْعَلُنَّsecond masculine plural
لَتُفْعَلِنَّsecond feminine singular
لَتُفْعَلَانِّsecond feminine dual
لَتُفْعَلْنَانِّsecond feminine plural
لَتُفْعَلَنَّ refers to one male addressee, while لَتُفْعَلِنَّ addresses one woman. Both are passive; fatḥa versus kasrah before the heavy nūn differentiates them. The other forms preserve the relevant distinctions of number and gender.