Error 500, change of admin passwords

[pbt]

Hello there. If I change admin password have Error 500.
After it:
* password really changed
* session terminated
* no e-mail notification (outbound mail is configured)

In data/logs/ no any fresh file.

php-error.log of server:

PHP Fatal error: Undefined constant 'JSON_PRESERVE_ZERO_FRACTION' in */EspoCRM/application/Espo/Core/Htmlizer/Htmlizer.php on line 185
[09-Jan-2019 15:46:10 UTC] PHP Fatal error: Undefined constant 'JSON_PRESERVE_ZERO_FRACTION' in */EspoCRM/application/Espo/Core/Htmlizer/Htmlizer.php on line 185
[09-Jan-2019 15:46:34 UTC]

[tanya]

Hello,
what version of php do you use? possible you need to upgrade it

[pbt]

Current version on server PHP 5.6, Espo CRM version of begin of January, 5.5.3?

[tanya]

JSON_PRESERVE_ZERO_FRACTION flag is available since PHP 5.6.6.
As I now EspoCRM will deprecate support php older the 7.1 soon

[pbt]

I will modify all to PHP 7.1 and inform about the missing or presence of the error in this thread