[8.12](backport #3531) [RUM] Remove FID and add INP

docs/en/observability/exploratory-data-visualizations.asciidoc

@@ -53,7 +53,7 @@ perceived performance of your web applications based on the metric you select.
 loading performance, load responsiveness, and visual stability, for each of your
 web applications.
 
-To learn more about metrics such as Largest contentful paint, First input delay,
+To learn more about metrics such as Largest contentful paint, Interaction to next paint,
 and Cumulative layout shift, see {observability-guide}/user-experience.html#user-experience-metrics[{user-experience} metrics].
 
 |Device distribution
@@ -168,7 +168,7 @@ The following table shows which data types are available for each report type:
 | Page views | | {yes-icon} |
 | Backend time | | {yes-icon} |
 | Total blocking time | | {yes-icon} |
-| First input delay | | {yes-icon} |
+| Interaction to next paint | | {yes-icon} |
 | Latency | | | {yes-icon}
 | Throughput | | | {yes-icon}
 | System memory usage | | | {yes-icon}

docs/en/observability/user-experience.asciidoc

@@ -134,22 +134,44 @@ https://web.dev/vitals/[Core Web Vitals] is a recent initiative from Google to i
 metrics that better categorize good and bad sites by quantifying the real-world user experience.
 This is done by looking at three key metrics: loading performance, visual stability, and interactivity:
 
-[role="screenshot"]
-image::images/web-dev-vitals.png[Web vitals (image source: https://web.dev/vitals)]
-
-Image source: https://web.dev/vitals/[web.dev/vitals]
-
 Largest contentful paint (LCP)::
 Loading performance. LCP is the timestamp when the main content of a page has likely loaded.
 To users, this is the _perceived_ loading speed of your site.
 To provide a good user experience, Google recommends an LCP of fewer than 2.5 seconds.
 footnote:[Source: https://web.dev/lcp/[web.dev]]
 
-First input delay (FID)::
-Load responsiveness. FID measures the time between a user's first interaction with a page, like a click,
-and when the page can respond to those interactions.
-To provide a good user experience, Google recommends a FID of less than 100 milliseconds.
-footnote:[Source: https://web.dev/fid/[web.dev]]
+Interaction to next paint (INP)::
+Responsiveness to user interactions.
+The INP value comes from measuring the latency of all click, tap, and keyboard interactions that happen throughout a single page visit and choosing the longest interaction observed.
+To provide a good user experience, Google recommends an INP of fewer than 200 milliseconds.
+footnote:[Source: https://web.dev/articles/inp[web.dev]]
+
+[NOTE]
+====
+Previous {kib} versions included the metric https://web.dev/fid/[First input delay (FID)] in the User Experience app.
+Starting with version 8.12, FID was replaced with _Interaction to next paint (INP)_.
+The APM RUM agent started collecting INP data in version 5.16.0.
+If you use an earlier version of the RUM agent with {kib} version 8.12 or later, it will _not_ capture INP data
+and there will be _no data_ to show in the User Experience app:
+
+[cols="1,1,1"]
+|===
+|
+|*Kibana version ≥{nbsp}8.12*
+|*Kibana version <{nbsp}8.12*
+
+|*RUM agent version ≥{nbsp}5.16.0*
+|INP data will be visible.
+|FID data will be visible.
+
+|*RUM agent version <{nbsp}5.16.0*
+|The INP section will be empty.
+|FID data will be visible.
+
+|===
+
+RUM agent version ≥{nbsp}5.16.0 will continue to collect FID metrics so, while FID metrics are not shown in the User Experience app in {kib} versions 8.12 and later, you can choose to visualize FID metrics in a {kibana-ref}/create-a-dashboard-of-panels-with-web-server-data.html[custom dashboard] or using {kibana-ref}/lens.html[Lens].
+====
 
 Cumulative layout shift (CLS)::
 Visual stability. Is content moving around because of `async` resource loading or dynamic content additions?