diff --git a/CHANGELOG.md b/CHANGELOG.md
index abb3abd..63a5bcf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+## 3.4.1
+  - Added backward compatibility of timestamp format to provide consistent fingerprint [#67](https://github.com/logstash-plugins/logstash-filter-fingerprint/pull/67)
+
 ## 3.4.0
   - Added support for 128bit murmur variant [#66](https://github.com/logstash-plugins/logstash-filter-fingerprint/pull/66).
 
diff --git a/lib/logstash/filters/fingerprint.rb b/lib/logstash/filters/fingerprint.rb
index e027109..3907d0e 100644
--- a/lib/logstash/filters/fingerprint.rb
+++ b/lib/logstash/filters/fingerprint.rb
@@ -24,6 +24,25 @@
 # To generate UUIDs, prefer the <<plugins-filters-uuid,uuid filter>>.
 class LogStash::Filters::Fingerprint < LogStash::Filters::Base
 
+  ##
+  # Logstash 8+ has variable-length serialization of timestamps
+  # that do not include subsecond info for whole-second timestamps.
+  # For backward-compatibility we refine the implementation to use
+  # our own three-decimal-place formatter for whole-second
+  # timestamps.
+  if LOGSTASH_VERSION.split('.').first.to_i >= 8
+    module MinimumSerializationLengthTimestamp
+      THREE_DECIMAL_INSTANT_FORMATTER = java.time.format.DateTimeFormatterBuilder.new.appendInstant(3).toFormatter
+      refine LogStash::Timestamp do
+        def to_s
+          return super unless nsec == 0
+          THREE_DECIMAL_INSTANT_FORMATTER.format(to_java.toInstant)
+        end
+      end
+    end
+    using MinimumSerializationLengthTimestamp
+  end
+
   INTEGER_MAX_32BIT = (1 << 31) - 1
   INTEGER_MIN_32BIT = -(1 << 31)
 
diff --git a/spec/filters/fingerprint_spec.rb b/spec/filters/fingerprint_spec.rb
index 48710cc..2ae946b 100644
--- a/spec/filters/fingerprint_spec.rb
+++ b/spec/filters/fingerprint_spec.rb
@@ -19,6 +19,10 @@
       plugin.filter(event)
     end
 
+    def ge_version_8
+      LOGSTASH_VERSION.split('.').first.to_i >= 8
+    end
+
     context "with a string field" do
       let(:data) { {"clientip" => "123.123.123.123" } }
       let(:config) { super().merge("source" => ["clientip" ]) }
@@ -273,7 +277,7 @@
     end
 
     context 'Timestamps' do
-      epoch_time = Time.at(0).gmtime
+      let(:epoch_time) { Time.at(0).gmtime }
       let(:config) { super().merge("source" => ['@timestamp']) }
 
       describe 'OpenSSL Fingerprinting' do
@@ -297,9 +301,35 @@
         let(:fingerprint_method) { "MURMUR3_128" }
         let(:data) { { "@timestamp" => epoch_time } }
         it "fingerprints the timestamp correctly" do
-          expect(fingerprint).to eq("37785b62a8cae473acc315d39b66d86e")
+          expect(fingerprint).to eq('37785b62a8cae473acc315d39b66d86e')
         end
       end
+
+      describe "fractional seconds" do
+        let(:fingerprint_method) { "MURMUR3" }
+        let(:data) { { "@timestamp" => epoch_time } }
+
+        describe "millisecond" do
+          let(:epoch_time) { LogStash::Timestamp.new('2000-01-01T05:00:00.12Z') }
+          it "fingerprints the timestamp correctly" do
+            expect(fingerprint).to eq(4263087275)
+          end
+        end
+
+        describe "microsecond" do
+          let(:epoch_time) { LogStash::Timestamp.new('2000-01-01T05:00:00.123456Z') }
+          it "fingerprints the timestamp correctly" do
+            expect(fingerprint).to eq(4188855160)
+          end
+        end if ge_version_8
+
+        describe "nanosecond" do
+          let(:epoch_time) { LogStash::Timestamp.new('2000-01-01T05:00:00.123456789Z') }
+          it "fingerprints the timestamp correctly" do
+            expect(fingerprint).to eq(3520111535)
+          end
+        end if ge_version_8
+      end
     end
 
     describe "post fingerprint execution triggers" do