Mezo, the developer of the Bitcoin L2 network, has completed a Series A financing round of $21 million, with Pantera Capital leading the investment and Multicoin, Hack VC, Draper Associates and others participating. Mezo uses the "HODL Proof" point system to utilize idle Bitcoin held by holders. The longer the holding time, the higher the contributor's "HODL score multiplier". Mezo will be launched together with the tBTC ecosystem developed by Thesis, which allows for "minimal trust" bridging to various ecosystems.