Added strict mode.

Closes #296
Closes #295

Author: ciscoheat

CHANGELOG.md

@@ -5,6 +5,12 @@ Headlines: Added, Changed, Deprecated, Removed, Fixed, Security
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- `strict` mode option added, to ensure that all fields exist when posted. In the default non-strict mode, non-existing fields were automatically using their default value.
+
 ## [1.12.0] - 2023-12-14
 
 ### Added