diff --git a/.rubocop.yml b/.rubocop.yml
index 9806211df..74645582a 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -31,6 +31,7 @@ Metrics/LineLength:
     - spec/engine/sync_manager_spec.rb
     - spec/engine/auth_api_client_spec.rb
     - spec/telemetry/synchronizer_spec.rb
+    - spec/splitclient/split_config_spec.rb
 
 Style/BracesAroundHashParameters:
   Exclude:
@@ -62,3 +63,4 @@ AllCops:
     - lib/splitclient-rb/engine/models/**/*
     - lib/splitclient-rb/engine/parser/**/*
     - spec/telemetry/synchronizer_spec.rb
+    - lib/splitclient-rb/engine/synchronizer.rb
diff --git a/CHANGES.txt b/CHANGES.txt
index 2022cdd6b..0e9633e04 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,5 +1,8 @@
 CHANGES
 
+7.3.1 (Jul 26, 2021)
+- Updated the synchronization flow to be more reliable in the event of an edge case generating delay in cache purge propagation, keeping the SDK cache properly synced.
+
 7.3.0 (Jul 12, 2021)
 - Updated SDK telemetry storage, metrics and updater to be more effective and send less often.
 - Fixed high cpu usage when api key is wrong.
diff --git a/lib/splitclient-rb.rb b/lib/splitclient-rb.rb
index d9657280e..a184a1732 100644
--- a/lib/splitclient-rb.rb
+++ b/lib/splitclient-rb.rb
@@ -85,13 +85,13 @@
 require 'splitclient-rb/engine/models/label'
 require 'splitclient-rb/engine/models/treatment'
 require 'splitclient-rb/engine/auth_api_client'
+require 'splitclient-rb/engine/back_off'
 require 'splitclient-rb/engine/push_manager'
 require 'splitclient-rb/engine/sync_manager'
 require 'splitclient-rb/engine/synchronizer'
 require 'splitclient-rb/utilitites'
 
-# SSE 
-require 'splitclient-rb/sse/event_source/back_off'
+# SSE
 require 'splitclient-rb/sse/event_source/client'
 require 'splitclient-rb/sse/event_source/event_parser'
 require 'splitclient-rb/sse/event_source/event_types'
diff --git a/lib/splitclient-rb/cache/fetchers/segment_fetcher.rb b/lib/splitclient-rb/cache/fetchers/segment_fetcher.rb
index 85ed13ceb..efd24bd2b 100644
--- a/lib/splitclient-rb/cache/fetchers/segment_fetcher.rb
+++ b/lib/splitclient-rb/cache/fetchers/segment_fetcher.rb
@@ -30,16 +30,19 @@ def call
         def fetch_segments_if_not_exists(names, cache_control_headers = false)
           names.each do |name|
             change_number = @segments_repository.get_change_number(name)
-
-            fetch_segment(name, cache_control_headers) if change_number == -1
+            
+            if change_number == -1
+              fetch_options = { cache_control_headers: cache_control_headers, till: nil }
+              fetch_segment(name, fetch_options) if change_number == -1
+            end
           end
         rescue StandardError => error
           @config.log_found_exception(__method__.to_s, error)
         end
 
-        def fetch_segment(name, cache_control_headers = false)
+        def fetch_segment(name, fetch_options = { cache_control_headers: false, till: nil })
           @semaphore.synchronize do
-            segments_api.fetch_segments_by_names([name], cache_control_headers)
+            segments_api.fetch_segments_by_names([name], fetch_options)
           end
         rescue StandardError => error
           @config.log_found_exception(__method__.to_s, error)
diff --git a/lib/splitclient-rb/cache/fetchers/split_fetcher.rb b/lib/splitclient-rb/cache/fetchers/split_fetcher.rb
index 91cb311bb..51534bab8 100644
--- a/lib/splitclient-rb/cache/fetchers/split_fetcher.rb
+++ b/lib/splitclient-rb/cache/fetchers/split_fetcher.rb
@@ -27,9 +27,9 @@ def call
           end
         end
 
-        def fetch_splits(cache_control_headers = false)
+        def fetch_splits(fetch_options = { cache_control_headers: false, till: nil })
           @semaphore.synchronize do
-            data = splits_since(@splits_repository.get_change_number, cache_control_headers)
+            data = splits_since(@splits_repository.get_change_number, fetch_options)
 
             data[:splits] && data[:splits].each do |split|
               add_split_unless_archived(split)
@@ -68,8 +68,8 @@ def splits_thread
           end
         end
 
-        def splits_since(since, cache_control_headers = false)
-          splits_api.since(since, cache_control_headers)
+        def splits_since(since, fetch_options = { cache_control_headers: false, till: nil })
+          splits_api.since(since, fetch_options)
         end
 
         def add_split_unless_archived(split)
diff --git a/lib/splitclient-rb/engine/api/segments.rb b/lib/splitclient-rb/engine/api/segments.rb
index ae27453d3..7f4a2f8d2 100644
--- a/lib/splitclient-rb/engine/api/segments.rb
+++ b/lib/splitclient-rb/engine/api/segments.rb
@@ -11,13 +11,14 @@ def initialize(api_key, segments_repository, config, telemetry_runtime_producer)
         @telemetry_runtime_producer = telemetry_runtime_producer
       end
 
-      def fetch_segments_by_names(names, cache_control_headers = false)
+      def fetch_segments_by_names(names, fetch_options = { cache_control_headers: false, till: nil })
         return if names.nil? || names.empty?
 
         names.each do |name|
           since = @segments_repository.get_change_number(name)
+
           loop do
-            segment = fetch_segment_changes(name, since, cache_control_headers)
+            segment = fetch_segment_changes(name, since, fetch_options)
             @segments_repository.add_to_segment(segment)
 
             @config.split_logger.log_if_debug("Segment #{name} fetched before: #{since}, \
@@ -32,9 +33,12 @@ def fetch_segments_by_names(names, cache_control_headers = false)
 
       private
 
-      def fetch_segment_changes(name, since, cache_control_headers = false)
+      def fetch_segment_changes(name, since, fetch_options = { cache_control_headers: false, till: nil })
         start = Time.now
-        response = get_api("#{@config.base_uri}/segmentChanges/#{name}", @api_key, { since: since }, cache_control_headers)
+
+        params = { since: since }
+        params[:till] = fetch_options[:till] unless fetch_options[:till].nil?
+        response = get_api("#{@config.base_uri}/segmentChanges/#{name}", @api_key, params, fetch_options[:cache_control_headers])
 
         if response.success?
           segment = JSON.parse(response.body, symbolize_names: true)
diff --git a/lib/splitclient-rb/engine/api/splits.rb b/lib/splitclient-rb/engine/api/splits.rb
index 3d0c1197f..99bbe5cee 100644
--- a/lib/splitclient-rb/engine/api/splits.rb
+++ b/lib/splitclient-rb/engine/api/splits.rb
@@ -10,10 +10,12 @@ def initialize(api_key, config, telemetry_runtime_producer)
         @telemetry_runtime_producer = telemetry_runtime_producer
       end
 
-      def since(since, cache_control_headers = false)
+      def since(since, fetch_options = { cache_control_headers: false, till: nil })
         start = Time.now
-
-        response = get_api("#{@config.base_uri}/splitChanges", @api_key, { since: since }, cache_control_headers)
+        
+        params = { since: since }
+        params[:till] = fetch_options[:till] unless fetch_options[:till].nil?
+        response = get_api("#{@config.base_uri}/splitChanges", @api_key, params, fetch_options[:cache_control_headers])
         if response.success?
           result = splits_with_segment_names(response.body)
 
diff --git a/lib/splitclient-rb/engine/back_off.rb b/lib/splitclient-rb/engine/back_off.rb
new file mode 100644
index 000000000..31097a097
--- /dev/null
+++ b/lib/splitclient-rb/engine/back_off.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: false
+
+module SplitIoClient
+  module Engine
+    BACKOFF_MAX_ALLOWED = 1.8
+    class BackOff
+      def initialize(back_off_base, attempt = 0, max_allowed = BACKOFF_MAX_ALLOWED)
+        @attempt = attempt
+        @back_off_base = back_off_base
+        @max_allowed = max_allowed
+      end
+
+      def interval
+        interval = 0
+        interval = (@back_off_base * (2**@attempt)) if @attempt.positive?
+        @attempt += 1
+
+        interval >= @max_allowed ? @max_allowed : interval
+      end
+
+      def reset
+        @attempt = 0
+      end
+    end
+  end
+end
diff --git a/lib/splitclient-rb/engine/push_manager.rb b/lib/splitclient-rb/engine/push_manager.rb
index 61f9eed3c..f30aa46e0 100644
--- a/lib/splitclient-rb/engine/push_manager.rb
+++ b/lib/splitclient-rb/engine/push_manager.rb
@@ -8,7 +8,7 @@ def initialize(config, sse_handler, api_key, telemetry_runtime_producer)
         @sse_handler = sse_handler
         @auth_api_client = AuthApiClient.new(@config, telemetry_runtime_producer)
         @api_key = api_key
-        @back_off = SplitIoClient::SSE::EventSource::BackOff.new(@config.auth_retry_back_off_base, 1)
+        @back_off = Engine::BackOff.new(@config.auth_retry_back_off_base, 1)
         @telemetry_runtime_producer = telemetry_runtime_producer
       end
 
diff --git a/lib/splitclient-rb/engine/synchronizer.rb b/lib/splitclient-rb/engine/synchronizer.rb
index 069521d7e..bbaae13ae 100644
--- a/lib/splitclient-rb/engine/synchronizer.rb
+++ b/lib/splitclient-rb/engine/synchronizer.rb
@@ -6,7 +6,9 @@ class Synchronizer
       include SplitIoClient::Cache::Fetchers
       include SplitIoClient::Cache::Senders
 
-      FORCE_CACHE_CONTROL_HEADERS = true
+      ON_DEMAND_FETCH_BACKOFF_BASE_SECONDS = 10
+      ON_DEMAND_FETCH_BACKOFF_MAX_WAIT_SECONDS = 60
+      ON_DEMAND_FETCH_BACKOFF_MAX_RETRIES = 10
 
       def initialize(
         repositories,
@@ -54,17 +56,116 @@ def stop_periodic_fetch
         @segment_fetcher.stop_segments_thread
       end
 
-      def fetch_splits
-        segment_names = @split_fetcher.fetch_splits(FORCE_CACHE_CONTROL_HEADERS)
-        @segment_fetcher.fetch_segments_if_not_exists(segment_names, FORCE_CACHE_CONTROL_HEADERS) unless segment_names.empty?
+      def fetch_splits(target_change_number)
+        return if target_change_number <= @splits_repository.get_change_number.to_i
+
+        fetch_options = { cache_control_headers: true, till: nil }
+
+        result = attempt_splits_sync(target_change_number,
+                                     fetch_options,
+                                     @config.on_demand_fetch_max_retries,
+                                     @config.on_demand_fetch_retry_delay_seconds,
+                                     false)
+
+        attempts = @config.on_demand_fetch_max_retries - result[:remaining_attempts]
+        if result[:success]
+          @segment_fetcher.fetch_segments_if_not_exists(result[:segment_names], true) unless result[:segment_names].empty?
+          @config.logger.debug("Refresh completed in #{attempts} attempts.") if @config.debug_enabled
+
+          return
+        end
+
+        fetch_options[:till] = target_change_number
+        result = attempt_splits_sync(target_change_number,
+                                     fetch_options,
+                                     ON_DEMAND_FETCH_BACKOFF_MAX_RETRIES,
+                                     nil,
+                                     true)
+
+        attempts = ON_DEMAND_FETCH_BACKOFF_MAX_RETRIES - result[:remaining_attempts]
+
+        if result[:success]
+          @segment_fetcher.fetch_segments_if_not_exists(result[:segment_names], true) unless result[:segment_names].empty?
+          @config.logger.debug("Refresh completed bypassing the CDN in #{attempts} attempts.") if @config.debug_enabled
+        else
+          @config.logger.debug("No changes fetched after #{attempts} attempts with CDN bypassed.") if @config.debug_enabled
+        end
+      rescue StandardError => error
+        @config.log_found_exception(__method__.to_s, error)
       end
 
-      def fetch_segment(name)
-        @segment_fetcher.fetch_segment(name, FORCE_CACHE_CONTROL_HEADERS)
+      def fetch_segment(name, target_change_number)
+        return if target_change_number <= @segments_repository.get_change_number(name).to_i
+
+        fetch_options = { cache_control_headers: true, till: nil }
+        result = attempt_segment_sync(name,
+                                      target_change_number,
+                                      fetch_options,
+                                      @config.on_demand_fetch_max_retries,
+                                      @config.on_demand_fetch_retry_delay_seconds,
+                                      false)
+
+        attempts = @config.on_demand_fetch_max_retries - result[:remaining_attempts]
+        if result[:success]
+          @config.logger.debug("Segment #{name} refresh completed in #{attempts} attempts.") if @config.debug_enabled
+
+          return
+        end
+
+        fetch_options = { cache_control_headers: true, till: target_change_number }
+        result = attempt_segment_sync(name,
+                                      target_change_number,
+                                      fetch_options,
+                                      ON_DEMAND_FETCH_BACKOFF_MAX_RETRIES,
+                                      nil,
+                                      true)
+
+        attempts = @config.on_demand_fetch_max_retries - result[:remaining_attempts]
+        if result[:success]
+          @config.logger.debug("Segment #{name} refresh completed bypassing the CDN in #{attempts} attempts.") if @config.debug_enabled
+        else
+          @config.logger.debug("No changes fetched for segment #{name} after #{attempts} attempts with CDN bypassed.") if @config.debug_enabled
+        end
+      rescue StandardError => error
+        @config.log_found_exception(__method__.to_s, error)
       end
 
       private
 
+      def attempt_segment_sync(name, target_cn, fetch_options, max_retries, retry_delay_seconds, with_backoff)
+        remaining_attempts = max_retries
+        backoff = Engine::BackOff.new(ON_DEMAND_FETCH_BACKOFF_BASE_SECONDS, 0, ON_DEMAND_FETCH_BACKOFF_MAX_WAIT_SECONDS) if with_backoff
+
+        loop do
+          remaining_attempts -= 1
+
+          @segment_fetcher.fetch_segment(name, fetch_options)
+
+          return sync_result(true, remaining_attempts) if target_cn <= @segments_repository.get_change_number(name).to_i
+          return sync_result(false, remaining_attempts) if remaining_attempts <= 0
+
+          delay = with_backoff ? backoff.interval : retry_delay_seconds
+          sleep(delay)
+        end
+      end
+
+      def attempt_splits_sync(target_cn, fetch_options, max_retries, retry_delay_seconds, with_backoff)
+        remaining_attempts = max_retries
+        backoff = Engine::BackOff.new(ON_DEMAND_FETCH_BACKOFF_BASE_SECONDS, 0, ON_DEMAND_FETCH_BACKOFF_MAX_WAIT_SECONDS) if with_backoff
+
+        loop do
+          remaining_attempts -= 1
+
+          segment_names = @split_fetcher.fetch_splits(fetch_options)
+
+          return sync_result(true, remaining_attempts, segment_names) if target_cn <= @splits_repository.get_change_number
+          return sync_result(false, remaining_attempts, segment_names) if remaining_attempts <= 0
+
+          delay = with_backoff ? backoff.interval : retry_delay_seconds
+          sleep(delay)
+        end
+      end
+
       def fetch_segments
         @segment_fetcher.fetch_segments
       end
@@ -87,6 +188,10 @@ def impressions_count_sender
       def start_telemetry_sync_task
         Telemetry::SyncTask.new(@config, @telemetry_synchronizer).call
       end
+
+      def sync_result(success, remaining_attempts, segment_names = nil)
+        { success: success, remaining_attempts: remaining_attempts, segment_names: segment_names }
+      end
     end
   end
 end
diff --git a/lib/splitclient-rb/split_config.rb b/lib/splitclient-rb/split_config.rb
index 468c3b0af..837e8a680 100644
--- a/lib/splitclient-rb/split_config.rb
+++ b/lib/splitclient-rb/split_config.rb
@@ -113,6 +113,9 @@ def initialize(opts = {})
 
       @sdk_start_time = Time.now
 
+      @on_demand_fetch_retry_delay_seconds = SplitConfig.default_on_demand_fetch_retry_delay_seconds
+      @on_demand_fetch_max_retries = SplitConfig.default_on_demand_fetch_max_retries
+
       startup_log
     end
 
@@ -278,6 +281,17 @@ def initialize(opts = {})
 
     attr_accessor :sdk_start_time
 
+    attr_accessor :on_demand_fetch_retry_delay_seconds    
+    attr_accessor :on_demand_fetch_max_retries
+
+    def self.default_on_demand_fetch_retry_delay_seconds
+      0.05
+    end
+
+    def self.default_on_demand_fetch_max_retries
+      10
+    end
+
     def self.default_impressions_mode
       :optimized
     end
diff --git a/lib/splitclient-rb/sse/event_source/back_off.rb b/lib/splitclient-rb/sse/event_source/back_off.rb
deleted file mode 100644
index b9a2f8c02..000000000
--- a/lib/splitclient-rb/sse/event_source/back_off.rb
+++ /dev/null
@@ -1,25 +0,0 @@
-# frozen_string_literal: false
-
-module SplitIoClient
-  module SSE
-    module EventSource
-      class BackOff
-        def initialize(back_off_base, attempt = 0)
-          @attempt = attempt
-          @back_off_base = back_off_base
-        end
-
-        def interval
-          interval = (@back_off_base * (2**@attempt)) if @attempt.positive?
-          @attempt += 1
-
-          interval || 0
-        end
-
-        def reset
-          @attempt = 0
-        end
-      end
-    end
-  end
-end
diff --git a/lib/splitclient-rb/sse/workers/segments_worker.rb b/lib/splitclient-rb/sse/workers/segments_worker.rb
index 6d5768e85..0a288ecc8 100644
--- a/lib/splitclient-rb/sse/workers/segments_worker.rb
+++ b/lib/splitclient-rb/sse/workers/segments_worker.rb
@@ -51,11 +51,7 @@ def perform
             cn = item[:change_number]
             @config.logger.debug("SegmentsWorker change_number dequeue #{segment_name}, #{cn}")
 
-            attempt = 0
-            while cn > @segments_repository.get_change_number(segment_name).to_i && attempt <= Workers::MAX_RETRIES_ALLOWED
-              @synchronizer.fetch_segment(segment_name)
-              attempt += 1
-            end
+            @synchronizer.fetch_segment(segment_name, cn)
           end
         end
 
diff --git a/lib/splitclient-rb/sse/workers/splits_worker.rb b/lib/splitclient-rb/sse/workers/splits_worker.rb
index ba4fd5273..03c780b14 100644
--- a/lib/splitclient-rb/sse/workers/splits_worker.rb
+++ b/lib/splitclient-rb/sse/workers/splits_worker.rb
@@ -3,8 +3,6 @@
 module SplitIoClient
   module SSE
     module Workers
-      MAX_RETRIES_ALLOWED = 10
-
       class SplitsWorker
         def initialize(synchronizer, config, splits_repository)
           @synchronizer = synchronizer
@@ -62,12 +60,7 @@ def kill_split(change_number, split_name, default_treatment)
         def perform
           while (change_number = @queue.pop)
             @config.logger.debug("SplitsWorker change_number dequeue #{change_number}")
-
-            attempt = 0
-            while change_number > @splits_repository.get_change_number.to_i && attempt <= Workers::MAX_RETRIES_ALLOWED
-              @synchronizer.fetch_splits
-              attempt += 1
-            end
+            @synchronizer.fetch_splits(change_number)
           end
         end
 
diff --git a/lib/splitclient-rb/version.rb b/lib/splitclient-rb/version.rb
index b204d940f..0e1cd8aef 100644
--- a/lib/splitclient-rb/version.rb
+++ b/lib/splitclient-rb/version.rb
@@ -1,3 +1,3 @@
 module SplitIoClient
-  VERSION = '7.3.0'
+  VERSION = '7.3.1'
 end
diff --git a/spec/engine/api/segments_spec.rb b/spec/engine/api/segments_spec.rb
index af112ae1a..755a2890f 100644
--- a/spec/engine/api/segments_spec.rb
+++ b/spec/engine/api/segments_spec.rb
@@ -43,6 +43,28 @@
       expect(log.string).to include ':added=>["max", "dan"]'
     end
 
+    it 'returns fetch_segments - with till param' do
+      stub_request(:get, 'https://sdk.split.io/api/segmentChanges/employees?since=-1&till=222334')
+        .with(headers: {
+                'Accept' => '*/*',
+                'Accept-Encoding' => 'gzip',
+                'Authorization' => 'Bearer',
+                'Connection' => 'keep-alive',
+                'Keep-Alive' => '30',
+                'Splitsdkversion' => "#{config.language}-#{config.version}"
+              })
+        .to_return(status: 200, body: segments)
+
+      fetch_options = { cache_control_headers: false, till: 222_334 }
+      returned_segment = segments_api.send(:fetch_segment_changes, 'employees', -1, fetch_options)
+
+      expect(returned_segment[:name]).to eq 'employees'
+
+      expect(log.string).to include "'employees' segment retrieved."
+      expect(log.string).to include "'employees' 2 added keys"
+      expect(log.string).to include ':added=>["max", "dan"]'
+    end
+
     it 'returns fetch_segments - checking headers when cache_control_headers is true' do
       stub_request(:get, 'https://sdk.split.io/api/segmentChanges/employees?since=-1')
         .with(headers: {
@@ -56,7 +78,8 @@
               })
         .to_return(status: 200, body: segments)
 
-      returned_segment = segments_api.send(:fetch_segment_changes, 'employees', -1, true)
+      fetch_options = { cache_control_headers: true, till: nil }
+      returned_segment = segments_api.send(:fetch_segment_changes, 'employees', -1, fetch_options)
 
       expect(returned_segment[:name]).to eq 'employees'
 
diff --git a/spec/engine/api/splits_spec.rb b/spec/engine/api/splits_spec.rb
index 374fda99c..bc2fcb034 100644
--- a/spec/engine/api/splits_spec.rb
+++ b/spec/engine/api/splits_spec.rb
@@ -47,7 +47,27 @@
       expect(log.string).to include returned_splits.to_s
     end
 
-    it 'returns the splits - checking headers when cache_control_headers is true ' do
+    it 'returns the splits - with till param' do
+      stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1&till=123123')
+        .with(headers: {
+                'Accept' => '*/*',
+                'Accept-Encoding' => 'gzip',
+                'Authorization' => 'Bearer',
+                'Connection' => 'keep-alive',
+                'Keep-Alive' => '30',
+                'Splitsdkversion' => "#{config.language}-#{config.version}"
+              })
+        .to_return(status: 200, body: splits)
+
+      fetch_options = { cache_control_headers: false, till: 123_123 }
+      returned_splits = splits_api.since(-1, fetch_options)
+      expect(returned_splits[:segment_names]).to eq(Set.new(%w[demo employees]))
+
+      expect(log.string).to include '2 splits retrieved. since=-1'
+      expect(log.string).to include returned_splits.to_s
+    end
+
+    it 'returns the splits - checking headers when cache_control_headers is true' do
       stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
         .with(headers: {
                 'Accept' => '*/*',
@@ -60,7 +80,8 @@
               })
         .to_return(status: 200, body: splits)
 
-      returned_splits = splits_api.since(-1, true)
+      fetch_options = { cache_control_headers: true, till: nil }
+      returned_splits = splits_api.since(-1, fetch_options)
       expect(returned_splits[:segment_names]).to eq(Set.new(%w[demo employees]))
 
       expect(log.string).to include '2 splits retrieved. since=-1'
diff --git a/spec/engine/synchronizer_spec.rb b/spec/engine/synchronizer_spec.rb
index 2ad3acfb4..87d4311ae 100644
--- a/spec/engine/synchronizer_spec.rb
+++ b/spec/engine/synchronizer_spec.rb
@@ -92,15 +92,114 @@
     mock_segment_changes('segment1', segment1, '-1')
     mock_segment_changes('segment1', segment1, '1470947453877')
 
-    synchronizer.fetch_splits
+    synchronizer.fetch_splits(0)
     expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.once
   end
 
+  it 'fetch_splits - with CDN bypassed' do
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')
+      .to_return(status: 200, body:
+    '{
+      "splits": [],
+      "since": -1,
+      "till": 1506703262918
+    }')
+
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918')
+      .to_return(status: 200, body:
+    '{
+      "splits": [],
+      "since": 1506703262918,
+      "till": 1506703262918
+    }')
+
+    stub_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918&till=1506703262920')
+      .to_return(status: 200, body:
+    '{
+      "splits": [],
+      "since": 1506703262918,
+      "till": 1506703262921
+    }')
+
+    synchronizer.fetch_splits(1_506_703_262_920)
+
+    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.once
+    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918')).to have_been_made.times(9)
+    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918&till=1506703262920')).to have_been_made.once
+  end
+
   it 'fetch_segment' do
-    mock_segment_changes('segment3', segment3, '-1')
+    stub_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=-1')
+      .to_return(status: 200, body:
+    '{
+      "name": "segment3",
+      "added": [],
+      "removed": [],
+      "since": -1,
+      "till": 111333
+    }')
+
+    stub_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=111333')
+      .to_return(status: 200, body:
+    '{
+      "name": "segment3",
+      "added": [],
+      "removed": [],
+      "since": 111333,
+      "till": 111333
+    }')
+
+    synchronizer.fetch_segment('segment3', 111_222)
+    expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=-1')).to have_been_made.once
+    expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=111333')).to have_been_made.once
+  end
 
-    synchronizer.fetch_segment('segment3')
+  it 'fetch_segment - with CDN bypassed' do
+    stub_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=-1')
+      .to_return(status: 200, body:
+    '{
+      "name": "segment3",
+      "added": [],
+      "removed": [],
+      "since": -1,
+      "till": 111333
+    }')
+
+    stub_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=111333')
+      .to_return(status: 200, body:
+    '{
+      "name": "segment3",
+      "added": [],
+      "removed": [],
+      "since": 111333,
+      "till": 111333
+    }')
+
+    stub_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=111333&till=111555')
+      .to_return(status: 200, body:
+    '{
+      "name": "segment3",
+      "added": [],
+      "removed": [],
+      "since": 111555,
+      "till": 111555
+    }')
+
+    stub_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=111555&till=111555')
+      .to_return(status: 200, body:
+    '{
+      "name": "segment3",
+      "added": [],
+      "removed": [],
+      "since": 111555,
+      "till": 111555
+    }')
+
+    synchronizer.fetch_segment('segment3', 111_555)
     expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=-1')).to have_been_made.once
+    expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=111333')).to have_been_made.times(10)
+    expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=111333&till=111555')).to have_been_made.once
+    expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment3?since=111555&till=111555')).to have_been_made.once
   end
 end
 
diff --git a/spec/splitclient/split_config_spec.rb b/spec/splitclient/split_config_spec.rb
index 8cb8ff041..8c5542fa8 100644
--- a/spec/splitclient/split_config_spec.rb
+++ b/spec/splitclient/split_config_spec.rb
@@ -31,6 +31,8 @@
       expect(configs.ip_addresses_enabled).to eq default_ip
       expect(configs.machine_name).to eq SplitIoClient::SplitConfig.machine_hostname(default_ip, nil, :redis)
       expect(configs.machine_ip).to eq SplitIoClient::SplitConfig.machine_ip(default_ip, nil, :redis)
+      expect(configs.on_demand_fetch_retry_delay_seconds).to eq SplitIoClient::SplitConfig.default_on_demand_fetch_retry_delay_seconds
+      expect(configs.on_demand_fetch_max_retries).to eq SplitIoClient::SplitConfig.default_on_demand_fetch_max_retries
     end
 
     it 'stores and retrieves correctly the customized values' do
diff --git a/spec/sse/event_source/back_off_spec.rb b/spec/sse/event_source/back_off_spec.rb
index 303a0ac69..b63268c4a 100644
--- a/spec/sse/event_source/back_off_spec.rb
+++ b/spec/sse/event_source/back_off_spec.rb
@@ -3,13 +3,13 @@
 require 'spec_helper'
 require 'http_server_mock'
 
-describe SplitIoClient::SSE::EventSource::BackOff do
-  subject { SplitIoClient::SSE::EventSource::BackOff }
+describe SplitIoClient::Engine::BackOff do
+  subject { SplitIoClient::Engine::BackOff }
 
   let(:log) { StringIO.new }
 
   it 'get intervals and reset attemps' do
-    back_off = subject.new(1)
+    back_off = subject.new(1, 0, 5)
 
     firts_interval = back_off.interval
     expect(firts_interval).to eq(0)
@@ -27,7 +27,7 @@
 
   it 'with custom config' do
     streaming_reconnect_back_off_base = 5
-    back_off = subject.new(streaming_reconnect_back_off_base)
+    back_off = subject.new(streaming_reconnect_back_off_base, 0, 30)
 
     firts_interval = back_off.interval
     expect(firts_interval).to eq(0)
@@ -42,4 +42,34 @@
     reset_interval = back_off.interval
     expect(reset_interval).to eq(0)
   end
+
+  it 'with max' do
+    streaming_reconnect_back_off_base = 5
+    back_off = subject.new(streaming_reconnect_back_off_base, 0, 30)
+
+    firts_interval = back_off.interval
+    expect(firts_interval).to eq(0)
+
+    second_interval = back_off.interval
+    expect(second_interval).to eq(10)
+
+    third_interval = back_off.interval
+    expect(third_interval).to eq(20)
+
+    third_interval = back_off.interval
+    expect(third_interval).to eq(30)
+
+    third_interval = back_off.interval
+    expect(third_interval).to eq(30)
+
+    third_interval = back_off.interval
+    expect(third_interval).to eq(30)
+
+    third_interval = back_off.interval
+    expect(third_interval).to eq(30)
+
+    back_off.reset
+    reset_interval = back_off.interval
+    expect(reset_interval).to eq(0)
+  end
 end
diff --git a/spec/sse/sse_handler_spec.rb b/spec/sse/sse_handler_spec.rb
index 75dac8781..f5943138d 100644
--- a/spec/sse/sse_handler_spec.rb
+++ b/spec/sse/sse_handler_spec.rb
@@ -62,7 +62,7 @@
     mock_segment_changes('segment2', segment2, '1470947453878')
     mock_segment_changes('segment3', segment3, '-1')
 
-    synchronizer.fetch_splits
+    synchronizer.fetch_splits(0)
   end
 
   context 'SPLIT UPDATE event' do
@@ -212,7 +212,7 @@
 
         expect(action_event).to eq(SplitIoClient::Constants::PUSH_CONNECTED)
         expect(sse_handler.sse_client.connected?).to eq(true)
-        expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=1470947453877')).to have_been_made.times(12)
+        expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=1470947453877')).to have_been_made.times(11)
 
         sse_handler.sse_client.close
 
diff --git a/spec/sse/workers/segments_worker_spec.rb b/spec/sse/workers/segments_worker_spec.rb
index 7d67f0c91..e0b11ba6c 100644
--- a/spec/sse/workers/segments_worker_spec.rb
+++ b/spec/sse/workers/segments_worker_spec.rb
@@ -68,7 +68,7 @@
 
       sleep(1)
 
-      expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=1470947453877')).to have_been_made.times(12)
+      expect(a_request(:get, 'https://sdk.split.io/api/segmentChanges/segment1?since=1470947453877')).to have_been_made.times(11)
     end
 
     it 'must not trigger fetch' do
diff --git a/spec/sse/workers/splits_worker_spec.rb b/spec/sse/workers/splits_worker_spec.rb
index 3274fc41e..bd4991661 100644
--- a/spec/sse/workers/splits_worker_spec.rb
+++ b/spec/sse/workers/splits_worker_spec.rb
@@ -49,7 +49,8 @@
 
     sleep(1)
 
-    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918')).to have_been_made.times(10)
+    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=-1')).to have_been_made.times(1)
+    expect(a_request(:get, 'https://sdk.split.io/api/splitChanges?since=1506703262918')).to have_been_made.at_least_times(2)
   end
 
   context 'add change number to queue' do