Brake fluid Dot 4+ (1 QT)

Brake fluid tyo DOT 4. This fluid is recommended in brake systems with or without ABS/ASR DOT 4 has a very high boiling point which reduces the risk for issues related to high temperature. What is the difference between DOT 4, DOT 5 and DOT 5.1? DOT 5 is silicon based and it is not used in cars anymore since it is not suitable for the ABS-systems and has not the same lubricating functions metal against metal like a glycol based fluid has (like DOT4 and DOT 5.1) Today's DOT is theoretically a DOT 5.1 when it comes to attributes. DOT 5.1 has overall a higher boiling point than DOT 4 but today's DOT 4 is stand up well against DOT 5.1