Serhii Symonov

Validation Muse for Contact Form 7 lets you override the default error copy that Contact Form 7 displays. Enable the plugin per form, then supply custom text for required notices and invalid email, URL, telephone, number, range, and date validation. Messages are stored in post meta so they stay with the form when you export/import.
Features:
<ul>
<li>Customize “required field” messages per field</li>
<li>Customize “invalid format” messages for email, URL, phone, number, range, and date fields</li>
<li>Enable/disable custom validation per form</li>
<li>Messages stored in post meta for easy export/import</li>
<li>Fully translatable with POT file included</li>
<li>Accessible admin interface with ARIA labels</li>
</ul>

Validation Muse for Contact Form 7

Fine-tune the validation copy for every Contact Form 7 field directly inside the form editor.

Sergey Biryukov

Allows to receive e-mail messages in character sets different from the blog charset.
Based on the original plugin by Anton Skorobogatov, the founder of Russian WordPress community.

wp_mail Cyrillic

Allows to receive e-mail messages in character sets different from the blog charset.

Validation Muse for Contact Form 7 vs wp_mail Cyrillic