diff --git a/.buildkite/commands/build-prototype.sh b/.buildkite/commands/build-prototype.sh
index 655cce15f..f86e4c407 100755
--- a/.buildkite/commands/build-prototype.sh
+++ b/.buildkite/commands/build-prototype.sh
@@ -9,5 +9,5 @@ install_cocoapods
 echo "--- :closed_lock_with_key: Installing Secrets"
 bundle exec fastlane run configure_apply
 
-echo "--- :hammer_and_wrench: Build and Upload to App Center"
-bundle exec fastlane build_and_upload_installable_build
+echo "--- :hammer_and_wrench: Build and Upload to Firebase App Distribution"
+bundle exec fastlane build_and_upload_prototype_build
diff --git a/.buildkite/pipeline.yml b/.buildkite/pipeline.yml
index 5e4fb659f..12f53eac6 100644
--- a/.buildkite/pipeline.yml
+++ b/.buildkite/pipeline.yml
@@ -40,9 +40,9 @@ steps:
       queue: "linter"
 
   #################
-  # Create Installable Build
+  # Prototype Build
   #################
-  - label: "🛠 Installable Build"
+  - label: "🛠 Prototype Build"
     command: ".buildkite/commands/build-prototype.sh"
     plugins: [$CI_TOOLKIT_PLUGIN]
     if: "build.pull_request.id != null || build.pull_request.draft"
diff --git a/Gemfile b/Gemfile
index 227e97178..75b6e6a75 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,9 +6,9 @@ source 'https://rubygems.org'
 gem 'cocoapods', '~> 1.14'
 gem 'danger-dangermattic', '~> 1.0'
 gem 'fastlane', '~> 2'
-gem 'fastlane-plugin-appcenter', '~> 2.1.2'
+gem 'fastlane-plugin-firebase_app_distribution', '~> 0.10'
 gem 'fastlane-plugin-sentry', '~> 1.6'
-gem 'fastlane-plugin-wpmreleasetoolkit', '~> 12.2'
+gem 'fastlane-plugin-wpmreleasetoolkit', '~> 13.0'
 
 group :screenshots, optional: true do
   gem 'rmagick', '~> 3.2.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index 485983558..17d2b1d3f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -205,10 +205,12 @@ GEM
       xcodeproj (>= 1.13.0, < 2.0.0)
       xcpretty (~> 0.4.0)
       xcpretty-travis-formatter (>= 0.0.3, < 2.0.0)
-    fastlane-plugin-appcenter (2.1.2)
+    fastlane-plugin-firebase_app_distribution (0.10.0)
+      google-apis-firebaseappdistribution_v1 (~> 0.3.0)
+      google-apis-firebaseappdistribution_v1alpha (~> 0.2.0)
     fastlane-plugin-sentry (1.22.0)
       os (~> 1.1, >= 1.1.4)
-    fastlane-plugin-wpmreleasetoolkit (12.4.0)
+    fastlane-plugin-wpmreleasetoolkit (13.0.0)
       activesupport (>= 6.1.7.1)
       buildkit (~> 1.5)
       chroma (= 0.2.0)
@@ -245,6 +247,10 @@ GEM
       representable (~> 3.0)
       retriable (>= 2.0, < 4.a)
       rexml
+    google-apis-firebaseappdistribution_v1 (0.3.0)
+      google-apis-core (>= 0.11.0, < 2.a)
+    google-apis-firebaseappdistribution_v1alpha (0.2.0)
+      google-apis-core (>= 0.11.0, < 2.a)
     google-apis-iamcredentials_v1 (0.17.0)
       google-apis-core (>= 0.11.0, < 2.a)
     google-apis-playcustomapp_v1 (0.13.0)
@@ -299,9 +305,9 @@ GEM
     naturally (2.2.1)
     netrc (0.11.0)
     nkf (0.2.0)
-    nokogiri (1.18.2-arm64-darwin)
+    nokogiri (1.18.4-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.18.2-x86_64-linux-gnu)
+    nokogiri (1.18.4-x86_64-linux-gnu)
       racc (~> 1.4)
     octokit (6.1.1)
       faraday (>= 1, < 3)
@@ -402,9 +408,9 @@ DEPENDENCIES
   cocoapods (~> 1.14)
   danger-dangermattic (~> 1.0)
   fastlane (~> 2)
-  fastlane-plugin-appcenter (~> 2.1.2)
+  fastlane-plugin-firebase_app_distribution (~> 0.10)
   fastlane-plugin-sentry (~> 1.6)
-  fastlane-plugin-wpmreleasetoolkit (~> 12.2)
+  fastlane-plugin-wpmreleasetoolkit (~> 13.0)
   rmagick (~> 3.2.0)
 
 BUNDLED WITH
diff --git a/fastlane/Fastfile b/fastlane/Fastfile
index 8809290e0..a77e0c005 100644
--- a/fastlane/Fastfile
+++ b/fastlane/Fastfile
@@ -23,7 +23,9 @@ PROJECT_SLUG = 'simplenote-ios'
 GITHUB_REPO = "#{ORGANIZATION}/#{PROJECT_SLUG}".freeze
 BUILDKITE_ORGANIZATION = ORGANIZATION
 BUILDKITE_PIPELINE = PROJECT_SLUG
-APPCENTER_OWNER_NAME = ORGANIZATION
+
+FIREBASE_APP_ID = '1:124902176124:ios:d21314b0300402801620f9'
+FIREBASE_TESTERS_GROUP = 'simplenote-ios---prototype-builds'
 
 WORKSPACE = 'Simplenote.xcworkspace'
 
@@ -105,24 +107,14 @@ platform :ios do
     )
   end
 
-  #####################################################################################
-  # build_and_upload_installable_build
-  # -----------------------------------------------------------------------------------
-  # This lane builds the app and upload it for adhoc testing
-  # -----------------------------------------------------------------------------------
-  # Usage:
-  # bundle exec fastlane build_and_upload_installable_build
+  # Build the app and upload it to Firebase App Distribution for adhoc testing
   #
-  # Example:
-  # bundle exec fastlane build_and_upload_installable_build
-  #####################################################################################
-  desc 'Builds and uploads an installable build'
-  lane :build_and_upload_installable_build do
+  desc 'Builds and uploads a prototype build'
+  lane :build_and_upload_prototype_build do
     update_certs_and_profiles_enterprise
 
-    # Get the current build version, and update it if needed
-    build_number = generate_installable_build_number
-    apply_build_number(build_number)
+    pr_or_branch = pull_request_number&.then { |num| "PR ##{num}" } || ENV.fetch('BUILDKITE_BRANCH', nil)
+    build_number = ENV.fetch('BUILDKITE_BUILD_NUMBER', '0')
 
     gym(
       scheme: 'Simplenote',
@@ -130,7 +122,9 @@ platform :ios do
       workspace: WORKSPACE,
       export_method: 'enterprise',
       clean: true,
+      xcargs: { VERSION_SHORT: pr_or_branch, VERSION_LONG: build_number },
       output_directory: OUTPUT_DIRECTORY_PATH,
+      output_name: 'Simplenote Alpha',
       export_team_id: TEAM_ID_ENTERPRISE,
       export_options: {
         method: 'enterprise',
@@ -141,16 +135,17 @@ platform :ios do
       }
     )
 
-    File.rename(File.join(OUTPUT_DIRECTORY_PATH, 'Simplenote.ipa'), File.join(OUTPUT_DIRECTORY_PATH, 'Simplenote Alpha.ipa'))
-
-    appcenter_upload(
-      api_token: EnvManager.get_required_env!('APPCENTER_API_TOKEN'),
-      owner_name: 'automattic',
-      owner_type: 'organization',
-      app_name: 'Simplenote-Installable-Builds',
-      file: File.join(OUTPUT_DIRECTORY_PATH, 'Simplenote Alpha.ipa'),
-      destinations: 'All-Users-of-Simplenote-Installable-Builds',
-      notify_testers: false
+    release_notes = <<~NOTES
+      Pull Request: ##{pull_request_number || 'N/A'}
+      Branch: `#{ENV.fetch('BUILDKITE_BRANCH', 'N/A')}`
+      Commit: #{ENV.fetch('BUILDKITE_COMMIT', 'N/A')[0...7]}
+    NOTES
+
+    firebase_app_distribution(
+      app: FIREBASE_APP_ID,
+      service_credentials_json_data: EnvManager.get_required_env!('FIREBASE_APP_DISTRIBUTION_ACCOUNT_KEY'),
+      release_notes: release_notes,
+      groups: FIREBASE_TESTERS_GROUP
     )
 
     sentry_upload_dsym(
@@ -160,31 +155,16 @@ platform :ios do
       dsym_path: lane_context[SharedValues::DSYM_OUTPUT_PATH]
     )
 
-    return if ENV['BUILDKITE_PULL_REQUEST'].nil?
-
-    post_installable_build_pr_comment
-  end
-
-  # Posts a comment on the current PR to inform where to download a given Installable Build that was just published to App Center.
-  #
-  # Use this only after `upload_to_app_center` as been called, as it announces how said App Center build can be installed.
-  #
-  # @called_by CI — especially, relies on `BUILDKITE_PULL_REQUEST` being defined
-  #
-  def post_installable_build_pr_comment
-    pr = ENV.fetch('BUILDKITE_PULL_REQUEST', nil)
-
-    return if pr.nil?
+    next if pull_request_number.nil?
 
+    # Post PR Comment
     comment_body = prototype_build_details_comment(
       app_display_name: 'Simplenote Prototype Build',
-      app_center_org_name: APPCENTER_OWNER_NAME,
       fold: true
     )
-
     comment_on_pr(
       project: GITHUB_REPO,
-      pr_number: Integer(pr),
+      pr_number: pull_request_number,
       reuse_identifier: 'installable-build-link--Simplenote-Installable-Builds',
       body: comment_body
     )
@@ -544,6 +524,12 @@ end
 # Helper Lanes
 ########################################################################
 
+def pull_request_number
+  # Buildkite sets this env var to the PR number if on a PR, but to 'false' (and not nil) if not on a PR
+  pr_num = ENV.fetch('BUILDKITE_PULL_REQUEST', 'false')
+  pr_num == 'false' ? nil : Integer(pr_num)
+end
+
 def fastlane_directory
   __dir__
 end
@@ -676,31 +662,6 @@ def submit_accounts_hash(accounts_hash)
   UI.message("Accounts state after write: #{fetch_test_accounts_hash}")
 end
 
-def apply_build_number(build_number)
-  versions = Xcodeproj::Config.new(File.new(VERSION_FILE_PATH)).to_hash
-  UI.message("Updating build version to #{build_number}")
-  versions['VERSION_LONG'] = build_number
-  new_config = Xcodeproj::Config.new(versions)
-  new_config.save_as(Pathname.new(VERSION_FILE_PATH))
-end
-
-def generate_installable_build_number
-  if ENV['BUILDKITE']
-    commit = ENV.fetch('BUILDKITE_COMMIT', nil)[0, 7]
-    branch = ENV.fetch('BUILDKITE_BRANCH', nil)
-    pr_num = ENV.fetch('BUILDKITE_PULL_REQUEST', nil)
-    build  = ENV.fetch('BUILDKITE_BUILD_ID', nil)
-
-    pr_num == 'false' ? "#{branch}-#{commit}-#{build}" : "pr#{pr_num}-#{commit}-#{build}"
-  else
-    repo = Git.open(PROJECT_ROOT_FOLDER)
-    commit = repo.current_branch
-    branch = repo.revparse('HEAD')[0, 7]
-
-    "#{branch}-#{commit}"
-  end
-end
-
 # Returns the release version of the app in the format `1.2` or `1.2.3` if it is a hotfix
 #
 def release_version_current
diff --git a/fastlane/env/project.env-example b/fastlane/env/project.env-example
index 280df896d..371b75b57 100644
--- a/fastlane/env/project.env-example
+++ b/fastlane/env/project.env-example
@@ -1,8 +1,6 @@
 INT_EXPORT_TEAM_ID=<Team id for internal distribution>
 EXT_EXPORT_TEAM_ID=<Team id for public distribution>
 
-APPCENTER_PUBLIC_ID=<AppCenter Public Id>
-
 FASTLANE_ITC_TEAM_ID=<Team ID for AppStore Connect>
 
 SENTRY_ORG_SLUG=<Org Slug for Sentry>
diff --git a/fastlane/env/user.env-example b/fastlane/env/user.env-example
index 254bd83be..d19f2fa68 100644
--- a/fastlane/env/user.env-example
+++ b/fastlane/env/user.env-example
@@ -1,3 +1,2 @@
 GHHELPER_ACCESS=<GitHub access token>
-APPCENTER_API_TOKEN=<AppCenter Api Token>
 SENTRY_AUTH_TOKEN=<Sentry Auth Token>
diff --git a/fastlane/example.env b/fastlane/example.env
index 4d561bbe6..22bffa10f 100644
--- a/fastlane/example.env
+++ b/fastlane/example.env
@@ -11,7 +11,6 @@ APP_STORE_CONNECT_API_KEY_KEY_ID=
 APP_STORE_CONNECT_API_KEY_ISSUER_ID=
 APP_STORE_CONNECT_API_KEY_KEY=
 
-APPCENTER_API_TOKEN=
 SENTRY_AUTH_TOKEN=
 
 UI_TESTS_ACCOUNT_EMAIL=