The ROS Wrapper for Intel RealSense Devices provides a ROS nodelet interface between the camera and the ROS system. Intel updates this ROS package on a fairly regular basis, which could lead to API version mismatch errors.

When this happens, the camera (sometimes) works fine on realsense-viewer but any code using the RealSense nodelet fails to compile. The specific error message is something like:

Failed to load nodelet [/camera/realsense2_camera] of type [realsense2_camera/RealSenseNodeFactory] even after refreshing the cache: API version mismatch: librealsense.so was compiled with API version 2.18.1 but the application was compiled with 2.16.4! Make sure correct version of the library is installed (make install)

1. 1. Navigate to your github repository folder for the ROS Wrapper for Intel RealSense Devices: cd ~/robot_ws/src/realsense
   2. To avoid loosing any local changes made, first do a git stash followed by a git pull. This will temporarily set your local changes aside while updating the repository from remote, and then merge your changes afterwards. The command sequence to use is: git stash then git pull origin development and lastly, git stash apply --index
   3. Finally, compile: cd ~/robot_ws then catkin_make

This will update your API version to the latest Intel release.