CocoaPods could not find compatible versions for pod "Firebase/CoreOnly"

I've update my flutter package to the last versions and now IOS doesn't work anymore.

When I try to update the pods it's shows this error:

    [!] CocoaPods could not find compatible versions for pod "Firebase/CoreOnly":
    In Podfile:
    cloud_firestore (from `.symlinks/plugins/cloud_firestore/ios`) was resolved to 0.0.1, which depends on
    Firebase/Firestore (~> 6.0) was resolved to 6.0.0, which depends on
    Firebase/CoreOnly (= 6.0.0)

    cloud_functions (from `.symlinks/plugins/cloud_functions/ios`) was resolved to 0.0.1, which depends on
    Firebase/Functions (~> 5.18) was resolved to 5.18.0, which depends on
    Firebase/CoreOnly (= 5.18.0)

Here my pubspec.yaml (Firebase related):

firebase_core: "^0.4.0"
firebase_auth: "^0.11.0"
firebase_analytics: "^3.0.0"  
cloud_firestore: "^0.11.0+1"
cloud_functions: "^0.3.0"
firebase_storage: "^3.0.0"
firebase_messaging: "^5.0.1"

I've made various steps to try to fix:

flutter clean
flutter build ios

pod install
pod update
pod repo update
pod install --repo-update

I've set platform :ios, '12.1' in Podfile and in Xcode as build target but nothing come back to works.

Here my podfile:

# Uncomment this line to define a global platform for your project
platform :ios, '12.1'

# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
ENV['COCOAPODS_DISABLE_STATS'] = 'true'

project 'Runner', {
  'Debug' => :debug,
  'Profile' => :release,
  'Release' => :release,
}

def parse_KV_file(file, separator='=')
  file_abs_path = File.expand_path(file)
  if !File.exists? file_abs_path
    return [];
  end
  pods_ary = []
  skip_line_start_symbols = ["#", "/"]
  File.foreach(file_abs_path) { |line|
      next if skip_line_start_symbols.any? { |symbol| line =~ /^\s*#{symbol}/ }
      plugin = line.split(pattern=separator)
      if plugin.length == 2
        podname = plugin[0].strip()
        path = plugin[1].strip()
        podpath = File.expand_path("#{path}", file_abs_path)
        pods_ary.push({:name => podname, :path => podpath});
      else
        puts "Invalid plugin specification: #{line}"
      end
  }
  return pods_ary
end

target 'Runner' do
  use_frameworks!

  # Prepare symlinks folder. We use symlinks to avoid having Podfile.lock
  # referring to absolute paths on developers' machines.
  system('rm -rf .symlinks')
  system('mkdir -p .symlinks/plugins')

  # Flutter Pods
  generated_xcode_build_settings = parse_KV_file('./Flutter/Generated.xcconfig')
  if generated_xcode_build_settings.empty?
    puts "Generated.xcconfig must exist. If you're running pod install manually, make sure flutter packages get is executed first."
  end
  generated_xcode_build_settings.map { |p|
    if p[:name] == 'FLUTTER_FRAMEWORK_DIR'
      symlink = File.join('.symlinks', 'flutter')
      File.symlink(File.dirname(p[:path]), symlink)
      pod 'Flutter', :path => File.join(symlink, File.basename(p[:path]))
    end
  }

  # Plugin Pods
  plugin_pods = parse_KV_file('../.flutter-plugins')
  plugin_pods.map { |p|
    symlink = File.join('.symlinks', 'plugins', p[:name])
    File.symlink(p[:path], symlink)
    pod p[:name], :path => File.join(symlink, 'ios')
  }
end

post_install do |installer|
  installer.pods_project.targets.each do |target|
    target.build_configurations.each do |config|
      config.build_settings['ENABLE_BITCODE'] = 'NO'
    end
  end
end

Try calling pod repo update

if the issue is not fixed

delete the Podfile.lock in the root directory, after that run pod install

Edit the minimum ios version in the podfile then run pod install.

Changing platform :ios, '9.0' to platform :ios, '10.0' then running pod install fixed it for me.