Fixes

src/Currency.php

@@ -16,9 +16,21 @@ class Currency extends Model {
   public function values(): ?array {
     if ($this->values === null) {
       $this->values = $this->parentOf(Value::class, [Model::CHILD_KEY => 'currency_id']);
+      if ($this->values) {
+        usort($this->values, function($a, $b) {
+          return $b->dateTime()->timestamp - $a->dateTime()->timestamp;
+        });
+      }
     }
     return $this->values;
   }
+  protected $latest;
+  public function latest(): ?Value {
+    if ($this->latest === null) {
+      $this->latest = $this->values()[0];
+    }
+    return $this->latest;
+  }
 
   protected static $fields = ['code', 'name'];
   public static function add(ModelFactory $factory, $info) {