php 7.0.21 won't load CURL library (1 reply)

Just installed php 7.0.21 and discovered that it won't load php_curl.dll. PHP Error log says

PHP Warning: PHP Startup: Unable to load dynamic library 'w:/wamp64/bin/php/php7.0.21/ext/php_curl.dll' - Die angegebene Prozedur wurde nicht gefunden.

The file is there, the path in php.ini to the extension dir is correct. Neither PHP 7.0.17 nor 7.1.0 show an error message when loaded. What is wrong?