Kibana versions 5.1.2 and 4.6.4 were released, featuring various bug fixes and improvements. Version 5.1.2 addressed issues such as errors triggered by using a secondary datetime field, reinstated the collapse button in the Timepicker, and improved spy tab performance on the Discover page. Version 4.6.4 incorporated many changes already present in version 5.0, including upgrading Node.js to version 6.9.0 for better memory management and resolving a segfault issue, along with improved support for Internet Explorer through shorter URLs and rendering performance enhancements in the Discover app. Additionally, this release upgraded the Hapi server to version 14.2.0 to accommodate the new Node.js version and made adjustments for better handling of percentile ranks aggregation and metric visualizations.