# Q&A## Q: How can I specify the version of a component?A: You can add the version declaration to the deployment configuration file. For example, you can specify the version of OceanBase-CE V3.1.0 in the deployment configuration file in the following format:```yamloceanbase-ce:version:3.1.0```## Q: How can I use a component of a specific version?A: You can add the package_hash or tag declaration to the deployment configuration file.For example, if you have tagged your compiled OceanBase-CE, you can specify it by tag. For example:```yamloceanbase-ce:tag:my-oceanbase```You can also use package_hash to specify a specific version. When you run an `obd mirror` command, OBD will return an MD5 value of the component. The MD5 value is the value of package_hash.```yamloceanbase-ce:package_hash:929df53459404d9b0c1f945e7e23ea4b89972069```## Q: How can I modify the startup process after I modify the code of OceanBase-CE?A: You can modify the startup plug-ins in the `~/.obd/plugins/oceanbase-ce/` directory. For example, after you add a new startup configuration item for OceanBase-CE V3.1.0, you can modify the `start.py` file in the `~/.obd/plugins/oceanbase-ce/3.1.0` directory.## Q:How to update OBD?A:You can use the `obd update` command to update OBD. When you are done with the update, use the `obd --version` command to confirm the version of OBD.