26650 is not obsolete. Dont be fooled by the mah on paper. The Shockli or Vapcell 5500mah 26650 will give you about 1,300mah in real world usage over the 5,000mah rated Samsung 50E, which is the highest capacity 21700 on the market. Test/review of Vapcell INR26650 5500mAh (Red) 2019