Version bits: Why did BitcoinXT choose to set THREE bits to 1 (0x20000007) to flag BIP101?
Bitcoin XT versions 0.11A through 0.11D supported the withdrawn BIP101, which set version = 0x20000007 as a best-guess nod toward the developing versionbits standard, while trying to maximize backward compatibility with the ways nodes might check for compatible versions.

Bitcoin XT version 0.11E supports BIP109, identical to Bitcoin Classic.