diff --git a/lib/chrono_model/adapter.rb b/lib/chrono_model/adapter.rb
index 8d8aca1..259fe91 100644
--- a/lib/chrono_model/adapter.rb
+++ b/lib/chrono_model/adapter.rb
@@ -7,7 +7,6 @@
 
 require 'chrono_model/adapter/ddl'
 require 'chrono_model/adapter/indexes'
-require 'chrono_model/adapter/tsrange'
 require 'chrono_model/adapter/upgrade'
 
 module ChronoModel
@@ -19,7 +18,6 @@ class Adapter < ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
     include ChronoModel::Adapter::Migrations
     include ChronoModel::Adapter::DDL
     include ChronoModel::Adapter::Indexes
-    include ChronoModel::Adapter::TSRange
     include ChronoModel::Adapter::Upgrade
 
     # The schema holding current data
diff --git a/lib/chrono_model/adapter/tsrange.rb b/lib/chrono_model/adapter/tsrange.rb
deleted file mode 100644
index e005e7f..0000000
--- a/lib/chrono_model/adapter/tsrange.rb
+++ /dev/null
@@ -1,72 +0,0 @@
-# frozen_string_literal: true
-
-module ChronoModel
-  class Adapter < ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
-    module TSRange
-      # HACK: Redefine tsrange parsing support, as it is broken currently.
-      #
-      # This self-made API is here because currently AR4 does not support
-      # open-ended ranges. The reasons are poor support in Ruby:
-      #
-      #   https://bugs.ruby-lang.org/issues/6864
-      #
-      # and an instable interface in Active Record:
-      #
-      #   https://github.com/rails/rails/issues/13793
-      #   https://github.com/rails/rails/issues/14010
-      #
-      # so, for now, we are implementing our own.
-      #
-      class Type < ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Range
-        OID = 3908
-
-        def cast_value(value)
-          return if value == 'empty'
-          return value if value.is_a?(::Array)
-
-          extracted = extract_bounds(value)
-
-          from = Conversions.string_to_utc_time extracted[:from]
-          to   = Conversions.string_to_utc_time extracted[:to]
-
-          [from, to]
-        end
-
-        def extract_bounds(value)
-          from, to = value[1..-2].split(',')
-
-          from_bound =
-            if value[1] == ',' || from == '-infinity'
-              nil
-            else
-              from[1..-2]
-            end
-
-          to_bound =
-            if value[-2] == ',' || to == 'infinity'
-              nil
-            else
-              to[1..-2]
-            end
-
-          {
-            from: from_bound,
-            to: to_bound
-          }
-        end
-      end
-
-      def initialize_type_map(m = type_map)
-        super.tap do
-          typ = ChronoModel::Adapter::TSRange::Type
-          oid = typ::OID
-
-          ar_type = type_map.fetch(oid)
-          cm_type = typ.new(ar_type.subtype, ar_type.type)
-
-          type_map.register_type oid, cm_type
-        end
-      end
-    end
-  end
-end
diff --git a/lib/chrono_model/time_machine/history_model.rb b/lib/chrono_model/time_machine/history_model.rb
index b76b2ba..fbdbc6e 100644
--- a/lib/chrono_model/time_machine/history_model.rb
+++ b/lib/chrono_model/time_machine/history_model.rb
@@ -214,7 +214,7 @@ def valid_from
       end
 
       def valid_to
-        validity.last
+        validity.end
       end
       alias as_of_time valid_to