--- redmine-4.0.2/lib/redmine/plugin.rb	2019-02-21 17:43:46.000000000 +0100
+++ /usr/share/redmine/redmine-4.0.2/lib/redmine/plugin.rb	2019-04-17 17:35:44.815629390 +0200
@@ -515,6 +515,23 @@
       def open
         Migrator.new(:up, migrations, nil)
       end
+
+      def set_current_plugin(p)
+	      @current_plugin = p
+      end
+
+
+      def get_all_versions(plugin = @current_plugin)
+        # Delete migrations that don't match .. to_i will work because the number comes first
+        @all_versions ||= {}
+        @all_versions[plugin.id.to_s] ||= begin
+          sm_table = ::ActiveRecord::SchemaMigration.table_name
+          migration_versions  = ActiveRecord::Base.connection.select_values("SELECT version FROM #{sm_table}")
+          versions_by_plugins = migration_versions.group_by { |version| version.match(/-(.*)$/).try(:[], 1) }
+          @all_versions       = versions_by_plugins.transform_values! {|versions| versions.map!(&:to_i).sort! }
+          @all_versions[plugin.id.to_s] || []
+        end
+      end
     end
 
     class Migrator < ActiveRecord::Migrator
@@ -527,7 +544,9 @@
           self.current_plugin = plugin
           return if current_version(plugin) == version
 
-          MigrationContext.new(plugin.migration_directory).migrate(version)
+          ctx = MigrationContext.new(plugin.migration_directory)
+          ctx.set_current_plugin(plugin)
+          ctx.migrate(version)
         end
 
         def get_all_versions(plugin = current_plugin)