As part of SERVER-18376, we are deprecating certain fields in the output of the buildInfo command and adding new fields for internal use only. The following fields in buildInfo are stable and won't change.

• version
• gitVersion
• versionArray
• bits
• debug
• maxBsonObjectSize
• storageEngines
• javascriptEngine

All other fields are for internal/debugging use and may change between release series.

The sysInfo field has been explicitly marked as deprecated, and in future versions will only report "deprecated" as its value. Eventually, it should be removed.

Drivers should only assume the stable fields are available going forward.