1 files changed, 40 insertions, 2 deletions
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index f840783059..fac91c31da 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,41 @@
+*   Ensure duration parsing is consistent across DST changes
+
+    Previously `ActiveSupport::Duration.parse` used `Time.current` and
+    `Time#advance` to calculate the number of seconds in the duration
+    from an arbitrary collection of parts. However as `advance` tries to
+    be consistent across DST boundaries this meant that either the
+    duration was shorter or longer depending on the time of year.
+
+    This was fixed by using an absolute reference point in UTC which
+    isn't subject to DST transitions. An arbitrary date of Jan 1st, 2000
+    was chosen for no other reason that it seemed appropriate.
+
+    Additionally, duration parsing should now be marginally faster as we
+    are no longer creating instances of `ActiveSupport::TimeWithZone`
+    every time we parse a duration string.
+
+    Fixes #26941.
+
+    *Andrew White*
+
+*   Use `Hash#compact` and `Hash#compact!` from Ruby 2.4. Old Ruby versions
+    will continue to get these methods from Active Support as before.
+
+    *Prathamesh Sonpatki*
+
+*   Fix `ActiveSupport::TimeZone#strptime`.
+    Support for timestamps in format of seconds (%s) and milliseconds (%Q).
+
+    Fixes #26840.
+
+    *Lev Denisov*
+
+*   Fix `DateAndTime::Calculations#copy_time_to`. Copy `nsec` instead of `usec`.
+
+    Jumping forward or backward between weeks now preserves nanosecond digits.
+
+    *Josua Schmid*
+
 *   Fix `ActiveSupport::TimeWithZone#in` across DST boundaries.
 
     Previously calls to `in` were being sent to the non-DST aware
@@ -8,10 +46,10 @@
         Time.zone = "US/Eastern"
 
         t = Time.zone.local(2016,11,6,1)
-        # => Sun, 06 Nov 2016 01:00:00 EDT -05:00 
+        # => Sun, 06 Nov 2016 01:00:00 EDT -05:00
 
         t.in(1.hour)
-        # => Sun, 06 Nov 2016 01:00:00 EST -05:00 
+        # => Sun, 06 Nov 2016 01:00:00 EST -05:00
 
     Fixes #26580.