function bp_core_time_since( $older_date, $newer_date = false ) {

	/**
	 * Filters whether or not to bypass BuddyPress' time_since calculations.
	 *
	 * @since 1.7.0
	 *
	 * @param bool   $value      Whether or not to bypass.
	 * @param string $older_date Earlier time from which we're calculating time elapsed.
	 * @param string $newer_date Unix timestamp of date to compare older time to.
	 */
	$pre_value = apply_filters( 'bp_core_time_since_pre', false, $older_date, $newer_date );
	if ( false !== $pre_value ) {
		return $pre_value;
	}

	$newer_date = (int) $newer_date;
	$args       = array(
		'older_date' => $older_date,
	);

	if ( $newer_date) {
		$args['newer_date'] = $newer_date;
	}

	// Calculate the time difference.
	$time_diff = bp_core_time_diff( $args );

	/**
	 * Filters the value to use if the time since is some time ago.
	 *
	 * @since 1.5.0
	 *
	 * @param string $value String representing the time since the older date.
	 */
	$ago_text = apply_filters(
		'bp_core_time_since_ago_text',
		/* translators: %s: the human time diff. */
		__( '%s ago', 'buddypress' )
	);

	/**
	 * Filters the value to use if the time since is right now.
	 *
	 * @since 1.5.0
	 *
	 * @param string $value String representing the time since the older date.
	 */
	$output = apply_filters( 'bp_core_time_since_right_now_text', __( 'right now', 'buddypress' ) );

	if ( is_array( $time_diff ) ) {
		$separator = _x( ',', 'Separator in time since', 'buddypress' ) . ' ';
		$diff_text = implode( $separator, $time_diff );
		$output    = sprintf( $ago_text, $diff_text );
	} elseif ( false === $time_diff ) {
		/**
		 * Filters the value to use if the time since is unknown.
		 *
		 * @since 1.5.0
		 *
		 * @param string $value String representing the time since the older date.
		 */
		$unknown_text = apply_filters( 'bp_core_time_since_unknown_text', __( 'sometime',  'buddypress' ) );
		$output       = sprintf( $ago_text, $unknown_text );
	}

	/**
	 * Filters the English-language representation of the time elapsed since a given date.
	 *
	 * @since 1.7.0
	 *
	 * @param string $output     Final 'time since' string.
	 * @param string $older_date Earlier time from which we're calculating time elapsed.
	 * @param string $newer_date Unix timestamp of date to compare older time to.
	 */
	return apply_filters( 'bp_core_time_since', $output, $older_date, $newer_date );
}