public String getIoTDBMajorVersion(String version) {
    return "UNKNOWN".equals(version)
        ? "UNKNOWN"
        : version.split("\\.")[0] + "." + version.split("\\.")[1];
  }
if the folders are relative paths, add IOTDB_DATA_HOME as the path prefix
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/conf/IoTDBConfig.java