sample.php

<?php
	// Filter is in wpforms/src/Forms/Token.php  -  get_valid_tokens();


	// Create our array of times to check before today. A user with a longer
	// cache time can extend this. A user with a shorter cache time can remove times.
	$valid_token_times_before = apply_filters(
		'wpforms_form_token_check_before_today',
			[
				( 2 * DAY_IN_SECONDS ), // Two days ago.
				( 1 * DAY_IN_SECONDS ), // One day ago.
			]
		);

	// Mostly to catch edge cases like the form page loading and submitting on two different days.
	// This probably won't be filtered by users too much, but they could extend it.
	$valid_token_times_after = apply_filters(
		'wpforms_form_token_check_after_today',
		[
			( 45 * MINUTE_IN_SECONDS ), // Add in 45 minutes past today to catch some midnight edge cases.
		]
	);


	// Example use of the token:
	add_filter( 'wpforms_form_token_check_before_today', 'example_add_longer_token_time_before' );

	/**
	 * Extend the expiration time. 
	 */
	function example_add_longer_token_time_before( $times ) {
		// Allow the token to persist for 5 days
		$times[] = 3 * DAY_IN_SECONDS;
		$times[] = 4 * DAY_IN_SECONDS;
		$times[] = 5 * DAY_IN_SECONDS;
	}

	add_filter( 'wpforms_form_token_check_after_today', 'example_add_longer_token_time_after' );



	/**
	 * This filter is to catch edge cases of someone loading the form and submitting,
	 * with the expiration happening in between. Making this longer allows for more leeway.
	 */
	function example_add_longer_token_time_after( $times ) {

		$times = array( DAY_IN_SECONDS );
	}