<?php
$json = <<<'JSON'
{
    "\u00fc": {"true": true, "false": false},
    "ü2": {"true": true, "false": false},
    "ue": {"true": true, "false": false},
    "⻪": {"true": true, "false": false}
}
JSON;

$jsonArray = json_decode($json, true);
$jsonStdClass = json_decode($json, false);

$t1 = $jsonArray["⻪"]["true"];
$t2 = $jsonArray["⻪"]["false"];
$t1_1 = true === $t1;
$t2_1 = false === $t2;

$breakHere = true;