PBFT is a protocol with three phases: pre-prepare, prepare and commit. In phase prepare and commit, each validator has to broadcast its vote for the proposed block. Upon receiving 2f+1 commit votes, each validator finalizes the block. Due to the broadcasting of votes, the complexity of communication grows as the square of the number of nodes, O(n^2). To reduce this, PDBFT2.0 establishes a leader for each voting round to collect votes from all validators. In addition, PDBFT2.0 adopts BLS threshold signatures to achieve linear communication. An (n,t)-threshold signature on a message m is a single, constant-sized aggregate signature that passes verification if and only if at least t out of the n participants sign m. Note that the verifier does not need to know the identities of the t signers. Each collector derives an (n,2f+1)-threshold signature after collecting 2f+1 votes. The threshold signature can be seen as a single signature with constant size. After that, the collector broadcasts the threshold signature and each validator can confirm that more than 2f+1 validators have voted for the proposed block via verify threshold signature.