Update changelog for 2.42 (#11909)

* Update changelog

Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>

* Reorder entries

Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>

---------

Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>

CHANGELOG.md

@@ -2,15 +2,24 @@
 
 ## 2.42.0-rc.0 / 2023-01-26
 
+This release comes with a bunch of feature coverage for native histograms and breaking changes.
+
+If you are trying native histograms already, we recommend you remove the `wal` directory when upgrading.
+Because the old WAL record for native histograms is not backward compatible in v2.42.0, this will lead to some data loss for the latest data.
+
+Additionally, if you scrape "float histograms" or use recording rules on native histograms in v2.42.0 (which writes float histograms),
+it is a one-way street since older versions do not support float histograms.
+
+* [CHANGE] **breaking** TSDB: Changed WAL record format for the experimental native histograms. #11783
 * [FEATURE] Add 'keep_firing_for' field to alerting rules. #11827
 * [FEATURE] Promtool: Add support of selecting timeseries for TSDB dump. #11872
 * [ENHANCEMENT] Agent: Native histogram support. #11842
-* [ENHANCEMENT] Histograms: Return actually useful counter reset hints. #11864
+* [ENHANCEMENT] Rules: Support native histograms in recording rules. #11838
 * [ENHANCEMENT] SD: Add container ID as a meta label for pod targets for Kubernetes. #11844
 * [ENHANCEMENT] SD: Add VM size label to azure service discovery. #11650
 * [ENHANCEMENT] Support native histograms in federation. #11830
-* [ENHANCEMENT] TSDB: Add gauge histogram support. #11783 #11840
-* [ENHANCEMENT] TSDB: Support FloatHistogram. #11522 #11817
+* [ENHANCEMENT] TSDB: Add gauge histogram support. #11783 #11840 #11814
+* [ENHANCEMENT] TSDB/Scrape: Support FloatHistogram that represents buckets as float64 values. #11522 #11817 #11716
 * [ENHANCEMENT] UI: Show individual scrape pools on /targets page. #11142
 
 ## 2.41.0 / 2022-12-20