I'm running into a problems when sending messages in Cyrillic with Contact form (as well as with Webform) on a Backdrop CMS site:

The message is received from the sender's email and the Cyrillic text reads normally when reading the message in Thunderbird / Windows 10 email client.

However, when receiving the message by an email client on an Android smartphone (the e-mail client is K9 Mail), the Cyrillic text is replaced with unintelligible characters.

Here is an example of the K9 email client for Android:

�������� Test (abc@email.com) �������������� ���������������� �� ������
������������������ ���� �������������� https://example.com/contact.

�������������� ���������� ���� �������� Test: 12345678

�������� 3 Test 1 PHP 8.3

When reading the same message through Roundcube web-based e-mail that is part of CPanel's web server applications, Cyrillic in messages is also unintelligible:

Тест Test (abc@email.com) изпрати съобщение чрез
страницата за контакти https://example.com/contact.

Телефонен номер на Тест Test: 12345678

Тест 3 Test 1 PHP 8.3

In both examples, it can be seen that the problem affects only the part of the text that is in Cyrillic, but the Latin is read normally. The problem affects both the Subject and the body of the message.

This problem only occurs when the PHP version of the web server is changed to PHP 8 (the problem occurs equally with PHP 8.0, PH 8.1, PHP 8.2).

If the web server is running PHP 7.4 there is no problem and Cyrillic messages sent through the message form are read normally.

For comparison, I also sent a message via a Webform module message form:

When running the web server with PHP 7.4, there are no problems again.

Changing the PHP version to 8.0 results in the following message sent via Webform

�������������� ��� 11
�������������� ���� ������������, �������������� 19 , 2023 - 5:39pm

���������� ���� ����������������������:

����������: Test
������, ��������������: Test
��������������: 12345
Email: abc@email.com
������������ ���� ��������������: ���������������� � ���� ��������������:

Test web server in this test is running PHP 8.0. If the web server in is running PHP 7.4 there are no problems with Cyrillic content in messages.

The output shows for me that it seems the problem is valid for both the contact form module and the messages sent through the webform module.

This problem is preventing me from upgrading the web servers of the wesites that I administer (they are all managed by cPanel) to PHP 8, and the lifetime of PHP 7 is decreasing alarmingly.

I would greatly appreciate any advice on how to try to solve this problem. Maybe there are some message code table settings that can be edited in the Backdrop settings.


Hi amilenkov. Can you check the dblog to see if there are any errors right after sending the messages? Also are you using any of the modules: SMTP? Mime Mail? Mail System?

Thanks for the reply, but I have to apologize, I don't know what dblog means.

There are no error descriptions in Recent log messages.

I can access the server through cPanel and FTP as well as phpMyAdmin but I don't know exactly where to check if these are the required tools.

I am not usung modules: SMTP? Mime Mail? Mail System? Only core message system.

Oh, I understand


No there are no error messages


Date Неделя, Ноември 19, 2023 - 5:03pm

User Anonymous (not verified)

Location https://domain.bg/contact

Referrer https://domain.bg/contact

СъобщениеТест Test (abc@email.com) sent an email regarding Контакти.


Hostname xxx.xxx.xxx.xxx


OK, so you are sending email with core functionality (no contrib), and there are no errors in the database log. Hmmm....

I would open an issue in the main Backdrop issue queue. This looks like a bug related to PHP 8. 

Hello argiepiano,

Above you wrote:

I would open an issue in the main Backdrop issue queue. This looks like a bug related to PHP 8.

If you are open an issue, could you send me a link so I can follow the discussion.

Or if I have to open an issue, could you tell me where to do it?

Thanks argiepiano,

I have a github account and will open an issue. I just need to think about how to present the problem and illustrate it with examples.

I asked the question to avoid duplicate issues.

Thank you!

Perhaps the reason this hasn't been noticed is that there aren't many users of Backdrop CMS who need Cyrillic.

As far as I am informed, I am the only user of the system in Bulgaria. However, I am responsible for the maintenance and development of more than 65 sites, and now all of them are with Backdrop CMS :) (except for one with Drupal 6)

That's probably right - not many other users sending email in Cyrillic. I know very little about multi-language emails in general, so I'm afraid I can't help, but if you post an issue you may get replies from people more familiar with this.