An unsigned quantity is always >= 0
@ -103,8 +103,8 @@ bool HardFork::add(uint8_t block_version, uint64_t height)
while (versions.size() >= window_size) {
const uint8_t old_version = versions.front();
assert(last_versions[old_version] >= 1);
last_versions[old_version]--;
assert(last_versions[old_version] >= 0);
versions.pop_front();
}