diff --git a/contract-tests/client_entity.rb b/contract-tests/client_entity.rb
index 5df1f56a..8d061005 100644
--- a/contract-tests/client_entity.rb
+++ b/contract-tests/client_entity.rb
@@ -52,10 +52,6 @@ def initialize(log, config)
         data_system.fdv1_compatible_synchronizer(build_fdv1_fallback_builder(fdv1_fallback_config))
       end
 
-      if data_system_config[:payloadFilter]
-        opts[:payload_filter_key] = data_system_config[:payloadFilter]
-      end
-
       opts[:data_system_config] = data_system.build
     elsif config[:streaming]
       streaming = config[:streaming]
diff --git a/lib/ldclient-rb/impl/data_system/polling.rb b/lib/ldclient-rb/impl/data_system/polling.rb
index 078352ef..9613a752 100644
--- a/lib/ldclient-rb/impl/data_system/polling.rb
+++ b/lib/ldclient-rb/impl/data_system/polling.rb
@@ -309,17 +309,9 @@ def initialize(sdk_key, http_config, config)
         # @return [Result]
         #
         def fetch(selector)
-          query_params = []
-          query_params << ["filter", @config.payload_filter_key] unless @config.payload_filter_key.nil?
-
-          if selector && selector.defined?
-            query_params << ["basis", selector.state]
-          end
-
           uri = @poll_uri
-          if query_params.any?
-            filter_query = URI.encode_www_form(query_params)
-            uri = "#{uri}?#{filter_query}"
+          if selector && selector.defined?
+            uri = "#{uri}?#{URI.encode_www_form(basis: selector.state)}"
           end
 
           headers = {}
@@ -384,7 +376,7 @@ class HTTPFDv1PollingRequester
         #
         # @param sdk_key [String]
         # @param http_config [HttpConfigOptions] HTTP connection settings
-        # @param config [LaunchDarkly::Config] Used for global header settings and payload_filter_key
+        # @param config [LaunchDarkly::Config] Used for global header settings
         #
         def initialize(sdk_key, http_config, config)
           @etag = nil
@@ -401,14 +393,7 @@ def initialize(sdk_key, http_config, config)
         # @return [Result]
         #
         def fetch(selector)
-          query_params = []
-          query_params << ["filter", @config.payload_filter_key] unless @config.payload_filter_key.nil?
-
           uri = @poll_uri
-          if query_params.any?
-            filter_query = URI.encode_www_form(query_params)
-            uri = "#{uri}?#{filter_query}"
-          end
 
           headers = {}
           Impl::Util.default_http_headers(@sdk_key, @config).each { |k, v| headers[k] = v }
diff --git a/lib/ldclient-rb/impl/data_system/streaming.rb b/lib/ldclient-rb/impl/data_system/streaming.rb
index d3c9a5f4..ad00531b 100644
--- a/lib/ldclient-rb/impl/data_system/streaming.rb
+++ b/lib/ldclient-rb/impl/data_system/streaming.rb
@@ -182,7 +182,6 @@ def sync(ss)
             client.query_params do
               selector = ss.selector
               {
-                "filter" => @config.payload_filter_key,
                 "basis" => (selector.state if selector&.defined?),
               }.compact
             end
diff --git a/spec/impl/data_system/streaming_headers_spec.rb b/spec/impl/data_system/streaming_headers_spec.rb
index 707db3a2..f7c79417 100644
--- a/spec/impl/data_system/streaming_headers_spec.rb
+++ b/spec/impl/data_system/streaming_headers_spec.rb
@@ -15,7 +15,6 @@ module DataSystem
             "Config",
             logger: logger,
             stream_uri: "https://stream.example.com",
-            payload_filter_key: nil,
             socket_factory: nil,
             initial_reconnect_delay: 1,
             instance_id: nil
diff --git a/spec/impl/data_system/streaming_synchronizer_spec.rb b/spec/impl/data_system/streaming_synchronizer_spec.rb
index 6a7ba32e..261b7368 100644
--- a/spec/impl/data_system/streaming_synchronizer_spec.rb
+++ b/spec/impl/data_system/streaming_synchronizer_spec.rb
@@ -17,7 +17,6 @@ module DataSystem
             "Config",
             logger: logger,
             stream_uri: "https://stream.example.com",
-            payload_filter_key: nil,
             socket_factory: nil,
             initial_reconnect_delay: 1,
             instance_id: nil