With this release the client_java simpleclient switches to the OpenMetrics data model and adds support for various new OpenMetrics-related features. This should be largely seamless, however any counters which lack a _total suffix on their sample will now have it added. If you'd prefer to make that change more gradually, you should change your metric names before upgrading to this version.
[CHANGE] Switch data model to OpenMetrics. Primarily this means that _total if present is stripped from the metric name of counters, and _total is now always a suffix on the sample value. This means that all Counter samples now have a _total suffix (#615)
[CHANGE] The io.prometheus.client.Collector.Type enum' value UNTYPED renamed to UNKNOWN (#615)
[FEATURE] Add Info and Enumeration metric types for direct instrumentation (#615)
[FEATURE] Counter, Summary, and Histogram metrics now expose a _created sample with when their child was created (#615)
[FEATURE] Add support for units (#615)
[FEATURE] Add gauge histograms, info, stateset for custom collectors (#615)
[FEATURE] Support negotiating and exposing OpenMetrics for all HTTP server exposition (#615 )
[FEATURE] Add ability to filter metrics in DropwizardExports (#574)
[ENHANCEMENT] Handle empty label values for the pushgateway (#553)
[ENHANCEMENT] Add Bill of Materials (#561)
[ENHANCEMENT] Count HTTP statuses returned for servlet filter (#560)
[BUGFIX] Make sure GZIPOutputStream is always closed for httpserver (#598)
[BUGFIX] Specify the charset of HTTPServer response for systems not using utf-8 by default (#564)