Redmine

we have some problem submitting an "ő" character in the subject or in the body. without this char, the system working as intended.

relevant info from production.log: x.x.x.x at 2016-04-22 11:46:39 +0200
Processing by IssuesController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"some_token", "issue"=>{"is_private"=>"0", "tracker_id"=>"2", "subject"=>"szerződés", "description"=>"Az issue akkor zárható, ha a szerződés aláírásra került.", "status_id"=>"1", "priority_id"=>"2", "assigned_to_id"=>"1", "parent_issue_id"=>"", "start_date"=>"2016-04-22", "due_date"=>"2016-04-29", "estimated_hours"=>"2", "done_ratio"=>"70", "checklists_attributes"=>{"0"=>{"is_done"=>"0", "subject"=>"végleges ajánlat egyeztetése", "_destroy"=>"false", "position"=>"1", "id"=>""}, "1461318375687s"=>{"is_done"=>"0", "subject"=>"szükséges információk megküldése", "_destroy"=>"false", "position"=>"1", "id"=>""}, "1461318384837s"=>{"is_done"=>"0", "subject"=>"szerződés megkötése", "_destroy"=>"false", "position"=>"1", "id"=>""}}}, "was_default_status"=>"1", "continue"=>"Létrehozás és folytatás", "project_id"=>"xyz"}
Current user: admin (id=1)
Mysql2::Error: Incorrect string value: '\xC5\x91d\xC3\xA9s' for column 'subject' at row 1: INSERT INTO `issues` (`project_id`, `author_id`, `start_date`, `tracker_id`, `status_id`, `subject`, `description`, `priority_id`, `assigned_to_id`, `due_date`, `estimated_hours`, `done_ratio`, `updated_on`, `created_on`, `lock_version`) VALUES (1, 1, '2016-04-22', 2, 1, 'szerződés', 'Az issue akkor zárható, ha a szerződés aláírásra került.', 2, 1, '2016-04-29', 2.0, 70, '2016-04-22 11:46:39', '2016-04-22 11:46:39', 0)
Completed 500 Internal Server Error in 87ms (ActiveRecord: 41.1ms)

ActiveRecord::StatementInvalid (Mysql2::Error: Incorrect string value: '\xC5\x91d\xC3\xA9s' for column 'subject' at row 1: INSERT INTO `issues` (`project_id`, `author_id`, `start_date`, `tracker_id`, `status_id`, `subject`, `description`, `priority_id`, `assigned_to_id`, `due_date`, `estimated_hours`, `done_ratio`, `updated_on`, `created_on`, `lock_version`) VALUES (1, 1, '2016-04-22', 2, 1, 'szerződés', 'Az issue akkor zárható, ha a szerződés aláírásra került.', 2, 1, '2016-04-29', 2.0, 70, '2016-04-22 11:46:39', '2016-04-22 11:46:39', 0)):
app/models/issue.rb:175:in `create_or_update'
app/controllers/issues_controller.rb:141:in `create'

environment:

$ ruby bin/about

sh: 1: svn: not found
sh: 1: darcs: not found
sh: 1: hg: not found
sh: 1: cvs: not found
sh: 1: bzr: not found
Environment:
  Redmine version                3.0.7.stable
  Ruby version                   1.9.3-p551 (2014-11-13) [x86_64-linux]
  Rails version                  4.2.3
  Environment                    production
  Database adapter               Mysql2
SCM:
  Git                            2.1.4
  Filesystem                     
Redmine plugins:
  progressive_projects_list      2.0.1
  redmine_checklists             3.1.3
  redmine_lightbox2              0.2.4
  redmine_mentions               0.0.1
  redmine_slack                  0.1
  time_logger                    0.5.3

config:

production:
  adapter: mysql2
  database: xxx
  host: localhost
  username: xxx
  password: "" 
  encoding: utf8