That's telling you that you'll need to restart some of the processes that the OneAgent is monitoring. Monitoring of the processes shouldn't be impacted, but for the processes to pick up the new version of the OneAgent a restart is needed.
here Dynatrace indicates you that you still have the monitoring activated for a process on that server but is using an older version (1.175.270 for this example)
Here is the process from 3. In this case Apache Tomcat, an DT indicates you that if you restart this process you get and updated version for that particular process, if you restart the Apache, 3 and 4 messages would disappear.
ADDITIONAL INFO. Here you can see that a newer version of the agent has been released. And you have an older one on that host.
ADDITIONAL INFO. As you can see in 5 this is your current OneAgent Version, but this is available even if the detail is collapsed.
The true delight is in the finding out rather than in the knowing.