diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8b97e55..98ace6b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## Unreleased
 
+### Removed
+
+- Handling of pre-1.0 subscriptions data.
+
+  If you're still using version 0.5 or below, please upgrade to 1.0 or 1.1 first with `handle_legacy_subscriptions` setting enabled.
+  See [release notes for version 1.0.0](https://github.com/anycable/graphql-anycable/releases/tag/v1.0.0) for details.
+
 ## 1.1.3 - 2022-03-11
 
 ### Changed
diff --git a/README.md b/README.md
index ab30e58..7d89c6b 100644
--- a/README.md
+++ b/README.md
@@ -140,7 +140,6 @@ GraphQL-AnyCable uses [anyway_config] to configure itself. There are several pos
     ```.env
     GRAPHQL_ANYCABLE_SUBSCRIPTION_EXPIRATION_SECONDS=604800
     GRAPHQL_ANYCABLE_USE_REDIS_OBJECT_ON_CLEANUP=true
-    GRAPHQL_ANYCABLE_HANDLE_LEGACY_SUBSCRIPTIONS=false
     GRAPHQL_ANYCABLE_USE_CLIENT_PROVIDED_UNIQ_ID=false
     ```
 
@@ -151,7 +150,6 @@ GraphQL-AnyCable uses [anyway_config] to configure itself. There are several pos
     production:
       subscription_expiration_seconds: 300 # 5 minutes
       use_redis_object_on_cleanup: false # For restricted redis installations
-      handle_legacy_subscriptions: false # For seamless upgrade from pre-1.0 versions
       use_client_provided_uniq_id: false # To avoid problems with non-uniqueness of Apollo channel identifiers
     ```
 
@@ -183,13 +181,6 @@ As in AnyCable there is no place to store subscription data in-memory, it should
     => 52ee8d65-275e-4d22-94af-313129116388
     ```
 
-    > For backward compatibility with pre-1.0 versions of this gem older `graphql-event:#{event.topic}` set containing subscription identifiers is also supported.
-    >
-    > ```
-    > SMEMBERS graphql-event:1:myStats:
-    > => 52ee8d65-275e-4d22-94af-313129116388
-    > ```
-
  3. Subscription data: `graphql-subscription:#{subscription_id}` hash contains everything required to evaluate subscription on trigger and create data for client.
 
     ```
diff --git a/lib/graphql/anycable/cleaner.rb b/lib/graphql/anycable/cleaner.rb
index d873d72..aab37c2 100644
--- a/lib/graphql/anycable/cleaner.rb
+++ b/lib/graphql/anycable/cleaner.rb
@@ -8,7 +8,6 @@ module Cleaner
       def clean
         clean_channels
         clean_subscriptions
-        clean_events
         clean_fingerprint_subscriptions
         clean_topic_fingerprints
       end
@@ -37,21 +36,6 @@ def clean_subscriptions
         end
       end
 
-      def clean_events
-        return unless config.handle_legacy_subscriptions
-
-        redis.scan_each(match: "#{adapter::SUBSCRIPTION_EVENTS_PREFIX}*") do |key|
-          subscription_id = key.sub(/\A#{adapter::SUBSCRIPTION_EVENTS_PREFIX}/, "")
-          next if redis.exists?(adapter::SUBSCRIPTION_PREFIX + subscription_id)
-
-          redis.smembers(key).each do |event_topic|
-            redis.srem(adapter::EVENT_PREFIX + event_topic, subscription_id)
-          end
-
-          redis.del(key)
-        end
-      end
-
       def clean_fingerprint_subscriptions
         redis.scan_each(match: "#{adapter::SUBSCRIPTIONS_PREFIX}*") do |key|
           redis.smembers(key).each do |subscription_id|
diff --git a/lib/graphql/anycable/config.rb b/lib/graphql/anycable/config.rb
index 5758c00..e225344 100644
--- a/lib/graphql/anycable/config.rb
+++ b/lib/graphql/anycable/config.rb
@@ -10,7 +10,6 @@ class Config < Anyway::Config
 
       attr_config subscription_expiration_seconds: nil
       attr_config use_redis_object_on_cleanup: true
-      attr_config handle_legacy_subscriptions: false
       attr_config use_client_provided_uniq_id: true
 
       on_load do
diff --git a/lib/graphql/anycable/tasks/clean_expired_subscriptions.rake b/lib/graphql/anycable/tasks/clean_expired_subscriptions.rake
index c28d696..c9043a6 100644
--- a/lib/graphql/anycable/tasks/clean_expired_subscriptions.rake
+++ b/lib/graphql/anycable/tasks/clean_expired_subscriptions.rake
@@ -18,11 +18,6 @@ namespace :graphql do
         GraphQL::AnyCable::Cleaner.clean_subscriptions
       end
 
-      # Clean up legacy subscription_ids from events for expired subscriptions
-      task :events do
-        GraphQL::AnyCable::Cleaner.clean_events
-      end
-
       # Clean up subscription_ids from event fingerprints for expired subscriptions
       task :fingerprint_subscriptions do
         GraphQL::AnyCable::Cleaner.clean_fingerprint_subscriptions
diff --git a/lib/graphql/subscriptions/anycable_subscriptions.rb b/lib/graphql/subscriptions/anycable_subscriptions.rb
index cf6a648..9096fc9 100644
--- a/lib/graphql/subscriptions/anycable_subscriptions.rb
+++ b/lib/graphql/subscriptions/anycable_subscriptions.rb
@@ -60,9 +60,6 @@ class AnyCableSubscriptions < GraphQL::Subscriptions
       FINGERPRINTS_PREFIX  = "graphql-fingerprints:"  # ZSET: To get fingerprints by topic
       SUBSCRIPTIONS_PREFIX = "graphql-subscriptions:" # SET:  To get subscriptions by fingerprint
       CHANNEL_PREFIX       = "graphql-channel:"       # SET:  Auxiliary structure for whole channel's subscriptions cleanup
-      # For backward compatibility:
-      EVENT_PREFIX = "graphql-event:"
-      SUBSCRIPTION_EVENTS_PREFIX = "graphql-subscription-events:"
 
       # @param serializer [<#dump(obj), #load(string)] Used for serializing messages before handing them to `.broadcast(msg)`
       def initialize(serializer: Serialize, **rest)
@@ -73,8 +70,6 @@ def initialize(serializer: Serialize, **rest)
       # An event was triggered.
       # Re-evaluate all subscribed queries and push the data over ActionCable.
       def execute_all(event, object)
-        execute_legacy(event, object) if config.handle_legacy_subscriptions
-
         fingerprints = redis.zrange(FINGERPRINTS_PREFIX + event.topic, 0, -1)
         return if fingerprints.empty?
 
@@ -109,17 +104,6 @@ def execute_grouped(fingerprint, subscription_ids, event, object)
         deliver(SUBSCRIPTIONS_PREFIX + fingerprint, result)
       end
 
-      # For migration from pre-1.0 graphql-anycable gem
-      def execute_legacy(event, object)
-        redis.smembers(EVENT_PREFIX + event.topic).each do |subscription_id|
-          next unless redis.exists?(SUBSCRIPTION_PREFIX + subscription_id)
-          result = execute_update(subscription_id, event, object)
-          next unless result
-
-          deliver(SUBSCRIPTION_PREFIX + subscription_id, result)
-        end
-      end
-
       # Disable this method as there is no fingerprint (it can be retrieved from subscription though)
       def execute(subscription_id, event, object)
         raise NotImplementedError, "Use execute_all method instead of execute to get actual event fingerprint"
@@ -206,19 +190,6 @@ def delete_subscription(subscription_id)
             pipeline.zremrangebyscore(key, '-inf', '0') if score.value.zero?
           end
         end
-        delete_legacy_subscription(subscription_id)
-      end
-
-      def delete_legacy_subscription(subscription_id)
-        return unless config.handle_legacy_subscriptions
-
-        events = redis.smembers(SUBSCRIPTION_EVENTS_PREFIX + subscription_id)
-        redis.pipelined do
-          events.each do |event_topic|
-            redis.srem(EVENT_PREFIX + event_topic, subscription_id)
-          end
-          redis.del(SUBSCRIPTION_EVENTS_PREFIX + subscription_id)
-        end
       end
 
       # The channel was closed, forget about it and its subscriptions