Today's translations are from Rohit Mehta, and from Bernard Bouanchaud, a french student of Sri Krishnamacharya and his son Sri TKV Desikachar (who was also one of my teacher's teachers).
Patanjali I.15:
Dispassion [non-attachment/letting go] is a condition free from all motives, whether arising from a desire for something that has been experienced or for something that has not yet been experienced (Mehta)
Nonattachment is the mastery of desire for perceived external objects, as well as for internal objects, heard or revealed (Bouanchaud)
And Patanjali I.15-16 from our interpreter Villoldo:
Let go of your attachments and discover self-mastery. Let go of your attachments. Free yourself from desire. The supreme nonattachment is when [we] accept life as it is right now. Our mind's drama does not distract [us] as [we] dwell in our True Self, needing nothing, wanting nothing.