diff --git a/lang/translations/ar.po b/lang/translations/ar.po
index 420d65e..9fdc4ae 100644
--- a/lang/translations/ar.po
+++ b/lang/translations/ar.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Arabic (https://www.transifex.com/ckeditor/teams/11143/ar/)\n"
diff --git a/lang/translations/az.po b/lang/translations/az.po
index 43cae98..16a1c9b 100644
--- a/lang/translations/az.po
+++ b/lang/translations/az.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Azerbaijani (https://www.transifex.com/ckeditor/teams/11143/az/)\n"
diff --git a/lang/translations/ca.po b/lang/translations/ca.po
index 2ebe973..a5afdfa 100644
--- a/lang/translations/ca.po
+++ b/lang/translations/ca.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Catalan (https://www.transifex.com/ckeditor/teams/11143/ca/)\n"
diff --git a/lang/translations/cs.po b/lang/translations/cs.po
index 2a90cb1..1fb50c4 100644
--- a/lang/translations/cs.po
+++ b/lang/translations/cs.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Czech (https://www.transifex.com/ckeditor/teams/11143/cs/)\n"
diff --git a/lang/translations/de.po b/lang/translations/de.po
index 03dd7bd..5cf799d 100644
--- a/lang/translations/de.po
+++ b/lang/translations/de.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: German (https://www.transifex.com/ckeditor/teams/11143/de/)\n"
diff --git a/lang/translations/en-au.po b/lang/translations/en-au.po
index 754e70d..eba896b 100644
--- a/lang/translations/en-au.po
+++ b/lang/translations/en-au.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: English (Australia) (https://www.transifex.com/ckeditor/teams/11143/en_AU/)\n"
diff --git a/lang/translations/en.po b/lang/translations/en.po
index e763a6a..9ecf9c4 100644
--- a/lang/translations/en.po
+++ b/lang/translations/en.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language: \n"
diff --git a/lang/translations/es.po b/lang/translations/es.po
index c8c1449..051008a 100644
--- a/lang/translations/es.po
+++ b/lang/translations/es.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Spanish (https://www.transifex.com/ckeditor/teams/11143/es/)\n"
diff --git a/lang/translations/et.po b/lang/translations/et.po
index f117e34..50547ac 100644
--- a/lang/translations/et.po
+++ b/lang/translations/et.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Estonian (https://www.transifex.com/ckeditor/teams/11143/et/)\n"
diff --git a/lang/translations/fa.po b/lang/translations/fa.po
index fe5ec86..0fae26d 100644
--- a/lang/translations/fa.po
+++ b/lang/translations/fa.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Persian (https://www.transifex.com/ckeditor/teams/11143/fa/)\n"
diff --git a/lang/translations/fr.po b/lang/translations/fr.po
index d588f23..37db547 100644
--- a/lang/translations/fr.po
+++ b/lang/translations/fr.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: French (https://www.transifex.com/ckeditor/teams/11143/fr/)\n"
diff --git a/lang/translations/gl.po b/lang/translations/gl.po
index 84e8b0d..72b8f90 100644
--- a/lang/translations/gl.po
+++ b/lang/translations/gl.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Galician (https://www.transifex.com/ckeditor/teams/11143/gl/)\n"
diff --git a/lang/translations/he.po b/lang/translations/he.po
index 03bd687..99f3df2 100644
--- a/lang/translations/he.po
+++ b/lang/translations/he.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Hebrew (https://www.transifex.com/ckeditor/teams/11143/he/)\n"
diff --git a/lang/translations/hr.po b/lang/translations/hr.po
index 0aeed2d..dc4fa6a 100644
--- a/lang/translations/hr.po
+++ b/lang/translations/hr.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Croatian (https://www.transifex.com/ckeditor/teams/11143/hr/)\n"
diff --git a/lang/translations/hu.po b/lang/translations/hu.po
index adc01a2..0d69015 100644
--- a/lang/translations/hu.po
+++ b/lang/translations/hu.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Hungarian (https://www.transifex.com/ckeditor/teams/11143/hu/)\n"
diff --git a/lang/translations/id.po b/lang/translations/id.po
index f241628..5f1e525 100644
--- a/lang/translations/id.po
+++ b/lang/translations/id.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Indonesian (https://www.transifex.com/ckeditor/teams/11143/id/)\n"
diff --git a/lang/translations/it.po b/lang/translations/it.po
index 27a045c..c3acc46 100644
--- a/lang/translations/it.po
+++ b/lang/translations/it.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Italian (https://www.transifex.com/ckeditor/teams/11143/it/)\n"
diff --git a/lang/translations/ku.po b/lang/translations/ku.po
index 51160fe..e14f68b 100644
--- a/lang/translations/ku.po
+++ b/lang/translations/ku.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Kurdish (https://www.transifex.com/ckeditor/teams/11143/ku/)\n"
diff --git a/lang/translations/nb.po b/lang/translations/nb.po
index 36ac503..fefc5c8 100644
--- a/lang/translations/nb.po
+++ b/lang/translations/nb.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Norwegian Bokmål (https://www.transifex.com/ckeditor/teams/11143/nb/)\n"
diff --git a/lang/translations/ne.po b/lang/translations/ne.po
index 7376fb8..61dc8e6 100644
--- a/lang/translations/ne.po
+++ b/lang/translations/ne.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Nepali (Nepal) (https://www.transifex.com/ckeditor/teams/11143/ne_NP/)\n"
diff --git a/lang/translations/nl.po b/lang/translations/nl.po
index 01f8ccf..1cb2ec0 100644
--- a/lang/translations/nl.po
+++ b/lang/translations/nl.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Dutch (https://www.transifex.com/ckeditor/teams/11143/nl/)\n"
diff --git a/lang/translations/no.po b/lang/translations/no.po
index 4f8dcb9..7361cf8 100644
--- a/lang/translations/no.po
+++ b/lang/translations/no.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Norwegian (https://www.transifex.com/ckeditor/teams/11143/no/)\n"
diff --git a/lang/translations/pl.po b/lang/translations/pl.po
index 875860e..27b5192 100644
--- a/lang/translations/pl.po
+++ b/lang/translations/pl.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Polish (https://www.transifex.com/ckeditor/teams/11143/pl/)\n"
diff --git a/lang/translations/pt-br.po b/lang/translations/pt-br.po
index 3719bcc..e22aca9 100644
--- a/lang/translations/pt-br.po
+++ b/lang/translations/pt-br.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Portuguese (Brazil) (https://www.transifex.com/ckeditor/teams/11143/pt_BR/)\n"
diff --git a/lang/translations/ru.po b/lang/translations/ru.po
index 488d03c..ba4a0fa 100644
--- a/lang/translations/ru.po
+++ b/lang/translations/ru.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Russian (https://www.transifex.com/ckeditor/teams/11143/ru/)\n"
diff --git a/lang/translations/sk.po b/lang/translations/sk.po
index f931b54..ec8f0f7 100644
--- a/lang/translations/sk.po
+++ b/lang/translations/sk.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Slovak (https://www.transifex.com/ckeditor/teams/11143/sk/)\n"
diff --git a/lang/translations/sq.po b/lang/translations/sq.po
index d98053d..7cf538c 100644
--- a/lang/translations/sq.po
+++ b/lang/translations/sq.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Albanian (https://www.transifex.com/ckeditor/teams/11143/sq/)\n"
diff --git a/lang/translations/sv.po b/lang/translations/sv.po
index 2da5878..4e7d3c6 100644
--- a/lang/translations/sv.po
+++ b/lang/translations/sv.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Swedish (https://www.transifex.com/ckeditor/teams/11143/sv/)\n"
diff --git a/lang/translations/tr.po b/lang/translations/tr.po
index b84bf73..ccf9396 100644
--- a/lang/translations/tr.po
+++ b/lang/translations/tr.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Turkish (https://www.transifex.com/ckeditor/teams/11143/tr/)\n"
diff --git a/lang/translations/uk.po b/lang/translations/uk.po
index 4ff4b6c..da41e95 100644
--- a/lang/translations/uk.po
+++ b/lang/translations/uk.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Ukrainian (https://www.transifex.com/ckeditor/teams/11143/uk/)\n"
diff --git a/lang/translations/zh-cn.po b/lang/translations/zh-cn.po
index 085a0b2..2a677b0 100644
--- a/lang/translations/zh-cn.po
+++ b/lang/translations/zh-cn.po
@@ -1,4 +1,15 @@
 # Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
+#
+#                                     !!! IMPORTANT !!!
+#
+#         Before you edit this file, please keep in mind that contributing to the project
+#                translations is possible ONLY via the Transifex online service.
+#
+#         To submit your translations, visit https://www.transifex.com/ckeditor/ckeditor5.
+#
+#                   To learn more, check out the official contributor's guide:
+#     https://ckeditor.com/docs/ckeditor5/latest/framework/guides/contributing/contributing.html
+#
 msgid ""
 msgstr ""
 "Language-Team: Chinese (China) (https://www.transifex.com/ckeditor/teams/11143/zh_CN/)\n"