diff --git a/.changeset/forty-ties-think.md b/.changeset/forty-ties-think.md
new file mode 100644
index 000000000..6f552c988
--- /dev/null
+++ b/.changeset/forty-ties-think.md
@@ -0,0 +1,5 @@
+---
+"@rebilly/client-php": patch
+---
+
+Make Plan.id readOnly Rebilly/api-definitions#1651
diff --git a/.changeset/great-waves-cheer.md b/.changeset/great-waves-cheer.md
new file mode 100644
index 000000000..c9b364032
--- /dev/null
+++ b/.changeset/great-waves-cheer.md
@@ -0,0 +1,5 @@
+---
+"@rebilly/client-php": patch
+---
+
+Make cashier request fields nullable Rebilly/api-definitions#1654
diff --git a/.changeset/hungry-goats-matter.md b/.changeset/hungry-goats-matter.md
new file mode 100644
index 000000000..4c591f6db
--- /dev/null
+++ b/.changeset/hungry-goats-matter.md
@@ -0,0 +1,5 @@
+---
+"@rebilly/client-php": patch
+---
+
+Add default values for cashier request Rebilly/api-definitions#1656
diff --git a/src/Api/CashierRequestsApi.php b/src/Api/CashierRequestsApi.php
index c69fc48c2..dc51125cc 100644
--- a/src/Api/CashierRequestsApi.php
+++ b/src/Api/CashierRequestsApi.php
@@ -18,6 +18,7 @@
 use GuzzleHttp\Utils;
 use Rebilly\Sdk\Collection;
 use Rebilly\Sdk\Model\CashierRequest;
+use Rebilly\Sdk\Model\PostCashierRequest;
 use Rebilly\Sdk\Paginator;
 
 class CashierRequestsApi
@@ -30,11 +31,11 @@ public function __construct(protected ?ClientInterface $client)
      * @return CashierRequest
      */
     public function create(
-        CashierRequest $cashierRequest,
+        PostCashierRequest $postCashierRequest,
     ): CashierRequest {
         $uri = '/cashier-requests';
 
-        $request = new Request('POST', $uri, body: Utils::jsonEncode($cashierRequest));
+        $request = new Request('POST', $uri, body: Utils::jsonEncode($postCashierRequest));
         $response = $this->client->send($request);
         $data = Utils::jsonDecode((string) $response->getBody(), true);
 
diff --git a/src/Model/CashierRequest.php b/src/Model/CashierRequest.php
index 542c8303a..4f6584bed 100644
--- a/src/Model/CashierRequest.php
+++ b/src/Model/CashierRequest.php
@@ -40,9 +40,6 @@ public function __construct(array $data = [])
         if (array_key_exists('customerId', $data)) {
             $this->setCustomerId($data['customerId']);
         }
-        if (array_key_exists('strategyId', $data)) {
-            $this->setStrategyId($data['strategyId']);
-        }
         if (array_key_exists('transactionId', $data)) {
             $this->setTransactionId($data['transactionId']);
         }
@@ -64,9 +61,6 @@ public function __construct(array $data = [])
         if (array_key_exists('expirationTime', $data)) {
             $this->setExpirationTime($data['expirationTime']);
         }
-        if (array_key_exists('customPropertySetId', $data)) {
-            $this->setCustomPropertySetId($data['customPropertySetId']);
-        }
         if (array_key_exists('propertiesSchema', $data)) {
             $this->setPropertiesSchema($data['propertiesSchema']);
         }
@@ -121,18 +115,6 @@ public function setCustomerId(string $customerId): static
         return $this;
     }
 
-    public function getStrategyId(): ?string
-    {
-        return $this->fields['strategyId'] ?? null;
-    }
-
-    public function setStrategyId(null|string $strategyId): static
-    {
-        $this->fields['strategyId'] = $strategyId;
-
-        return $this;
-    }
-
     public function getTransactionId(): ?string
     {
         return $this->fields['transactionId'] ?? null;
@@ -222,18 +204,6 @@ public function setExpirationTime(null|DateTimeImmutable|string $expirationTime)
         return $this;
     }
 
-    public function getCustomPropertySetId(): ?string
-    {
-        return $this->fields['customPropertySetId'] ?? null;
-    }
-
-    public function setCustomPropertySetId(null|string $customPropertySetId): static
-    {
-        $this->fields['customPropertySetId'] = $customPropertySetId;
-
-        return $this;
-    }
-
     public function getPropertiesSchema(): ?object
     {
         return $this->fields['propertiesSchema'] ?? null;
@@ -293,9 +263,6 @@ public function jsonSerialize(): array
         if (array_key_exists('customerId', $this->fields)) {
             $data['customerId'] = $this->fields['customerId'];
         }
-        if (array_key_exists('strategyId', $this->fields)) {
-            $data['strategyId'] = $this->fields['strategyId'];
-        }
         if (array_key_exists('transactionId', $this->fields)) {
             $data['transactionId'] = $this->fields['transactionId'];
         }
@@ -317,9 +284,6 @@ public function jsonSerialize(): array
         if (array_key_exists('expirationTime', $this->fields)) {
             $data['expirationTime'] = $this->fields['expirationTime']?->format(DateTimeInterface::RFC3339);
         }
-        if (array_key_exists('customPropertySetId', $this->fields)) {
-            $data['customPropertySetId'] = $this->fields['customPropertySetId'];
-        }
         if (array_key_exists('propertiesSchema', $this->fields)) {
             $data['propertiesSchema'] = $this->fields['propertiesSchema'];
         }
diff --git a/src/Model/FlexiblePlan.php b/src/Model/FlexiblePlan.php
index adc03be7c..1ac5826a1 100644
--- a/src/Model/FlexiblePlan.php
+++ b/src/Model/FlexiblePlan.php
@@ -287,14 +287,14 @@ public function setLinks(null|array $links): static
         return $this;
     }
 
-    public function getRecurringInterval(): ?SubscriptionOrderPlanRecurringInterval
+    public function getRecurringInterval(): SubscriptionOrderPlanRecurringInterval
     {
-        return $this->fields['recurringInterval'] ?? null;
+        return $this->fields['recurringInterval'];
     }
 
-    public function setRecurringInterval(null|SubscriptionOrderPlanRecurringInterval|array $recurringInterval): static
+    public function setRecurringInterval(SubscriptionOrderPlanRecurringInterval|array $recurringInterval): static
     {
-        if ($recurringInterval !== null && !($recurringInterval instanceof SubscriptionOrderPlanRecurringInterval)) {
+        if (!($recurringInterval instanceof SubscriptionOrderPlanRecurringInterval)) {
             $recurringInterval = SubscriptionOrderPlanRecurringInterval::from($recurringInterval);
         }
 
@@ -303,15 +303,15 @@ public function setRecurringInterval(null|SubscriptionOrderPlanRecurringInterval
         return $this;
     }
 
-    public function getTrial(): ?PlanTrial
+    public function getTrial(): TrialOnlyPlanTrial
     {
-        return $this->fields['trial'] ?? null;
+        return $this->fields['trial'];
     }
 
-    public function setTrial(null|PlanTrial|array $trial): static
+    public function setTrial(TrialOnlyPlanTrial|array $trial): static
     {
-        if ($trial !== null && !($trial instanceof PlanTrial)) {
-            $trial = PlanTrial::from($trial);
+        if (!($trial instanceof TrialOnlyPlanTrial)) {
+            $trial = TrialOnlyPlanTrial::from($trial);
         }
 
         $this->fields['trial'] = $trial;
diff --git a/src/Model/OrderItemPlan.php b/src/Model/OrderItemPlan.php
index 37938474d..4f0ad065c 100644
--- a/src/Model/OrderItemPlan.php
+++ b/src/Model/OrderItemPlan.php
@@ -287,14 +287,14 @@ public function setLinks(null|array $links): static
         return $this;
     }
 
-    public function getRecurringInterval(): ?SubscriptionOrderPlanRecurringInterval
+    public function getRecurringInterval(): SubscriptionOrderPlanRecurringInterval
     {
-        return $this->fields['recurringInterval'] ?? null;
+        return $this->fields['recurringInterval'];
     }
 
-    public function setRecurringInterval(null|SubscriptionOrderPlanRecurringInterval|array $recurringInterval): static
+    public function setRecurringInterval(SubscriptionOrderPlanRecurringInterval|array $recurringInterval): static
     {
-        if ($recurringInterval !== null && !($recurringInterval instanceof SubscriptionOrderPlanRecurringInterval)) {
+        if (!($recurringInterval instanceof SubscriptionOrderPlanRecurringInterval)) {
             $recurringInterval = SubscriptionOrderPlanRecurringInterval::from($recurringInterval);
         }
 
@@ -303,15 +303,15 @@ public function setRecurringInterval(null|SubscriptionOrderPlanRecurringInterval
         return $this;
     }
 
-    public function getTrial(): ?PlanTrial
+    public function getTrial(): TrialOnlyPlanTrial
     {
-        return $this->fields['trial'] ?? null;
+        return $this->fields['trial'];
     }
 
-    public function setTrial(null|PlanTrial|array $trial): static
+    public function setTrial(TrialOnlyPlanTrial|array $trial): static
     {
-        if ($trial !== null && !($trial instanceof PlanTrial)) {
-            $trial = PlanTrial::from($trial);
+        if (!($trial instanceof TrialOnlyPlanTrial)) {
+            $trial = TrialOnlyPlanTrial::from($trial);
         }
 
         $this->fields['trial'] = $trial;
diff --git a/src/Model/Plan.php b/src/Model/Plan.php
index 0af62ad42..f99b6c690 100644
--- a/src/Model/Plan.php
+++ b/src/Model/Plan.php
@@ -98,13 +98,6 @@ public function getId(): ?string
         return $this->fields['id'] ?? null;
     }
 
-    public function setId(null|string $id): static
-    {
-        $this->fields['id'] = $id;
-
-        return $this;
-    }
-
     public function getName(): string
     {
         return $this->fields['name'];
@@ -287,14 +280,14 @@ public function setLinks(null|array $links): static
         return $this;
     }
 
-    public function getRecurringInterval(): ?SubscriptionOrderPlanRecurringInterval
+    public function getRecurringInterval(): SubscriptionOrderPlanRecurringInterval
     {
-        return $this->fields['recurringInterval'] ?? null;
+        return $this->fields['recurringInterval'];
     }
 
-    public function setRecurringInterval(null|SubscriptionOrderPlanRecurringInterval|array $recurringInterval): static
+    public function setRecurringInterval(SubscriptionOrderPlanRecurringInterval|array $recurringInterval): static
     {
-        if ($recurringInterval !== null && !($recurringInterval instanceof SubscriptionOrderPlanRecurringInterval)) {
+        if (!($recurringInterval instanceof SubscriptionOrderPlanRecurringInterval)) {
             $recurringInterval = SubscriptionOrderPlanRecurringInterval::from($recurringInterval);
         }
 
@@ -303,15 +296,15 @@ public function setRecurringInterval(null|SubscriptionOrderPlanRecurringInterval
         return $this;
     }
 
-    public function getTrial(): ?PlanTrial
+    public function getTrial(): TrialOnlyPlanTrial
     {
-        return $this->fields['trial'] ?? null;
+        return $this->fields['trial'];
     }
 
-    public function setTrial(null|PlanTrial|array $trial): static
+    public function setTrial(TrialOnlyPlanTrial|array $trial): static
     {
-        if ($trial !== null && !($trial instanceof PlanTrial)) {
-            $trial = PlanTrial::from($trial);
+        if (!($trial instanceof TrialOnlyPlanTrial)) {
+            $trial = TrialOnlyPlanTrial::from($trial);
         }
 
         $this->fields['trial'] = $trial;
@@ -421,6 +414,13 @@ public function jsonSerialize(): array
         return $data;
     }
 
+    private function setId(null|string $id): static
+    {
+        $this->fields['id'] = $id;
+
+        return $this;
+    }
+
     private function setCurrencySign(null|string $currencySign): static
     {
         $this->fields['currencySign'] = $currencySign;
diff --git a/src/Model/PostCashierRequest.php b/src/Model/PostCashierRequest.php
new file mode 100644
index 000000000..d1aabbce7
--- /dev/null
+++ b/src/Model/PostCashierRequest.php
@@ -0,0 +1,220 @@
+<?php
+/**
+ * This source file is proprietary and part of Rebilly.
+ *
+ * (c) Rebilly SRL
+ *     Rebilly Ltd.
+ *     Rebilly Inc.
+ *
+ * @see https://www.rebilly.com
+ */
+
+declare(strict_types=1);
+
+namespace Rebilly\Sdk\Model;
+
+use DateTimeImmutable;
+use DateTimeInterface;
+use JsonSerializable;
+
+class PostCashierRequest implements JsonSerializable
+{
+    private array $fields = [];
+
+    public function __construct(array $data = [])
+    {
+        if (array_key_exists('websiteId', $data)) {
+            $this->setWebsiteId($data['websiteId']);
+        }
+        if (array_key_exists('customerId', $data)) {
+            $this->setCustomerId($data['customerId']);
+        }
+        if (array_key_exists('strategyId', $data)) {
+            $this->setStrategyId($data['strategyId']);
+        }
+        if (array_key_exists('currency', $data)) {
+            $this->setCurrency($data['currency']);
+        }
+        if (array_key_exists('amounts', $data)) {
+            $this->setAmounts($data['amounts']);
+        }
+        if (array_key_exists('customAmount', $data)) {
+            $this->setCustomAmount($data['customAmount']);
+        }
+        if (array_key_exists('redirectUrl', $data)) {
+            $this->setRedirectUrl($data['redirectUrl']);
+        }
+        if (array_key_exists('expirationTime', $data)) {
+            $this->setExpirationTime($data['expirationTime']);
+        }
+        if (array_key_exists('customPropertySetId', $data)) {
+            $this->setCustomPropertySetId($data['customPropertySetId']);
+        }
+    }
+
+    public static function from(array $data = []): self
+    {
+        return new self($data);
+    }
+
+    public function getWebsiteId(): string
+    {
+        return $this->fields['websiteId'];
+    }
+
+    public function setWebsiteId(string $websiteId): static
+    {
+        $this->fields['websiteId'] = $websiteId;
+
+        return $this;
+    }
+
+    public function getCustomerId(): string
+    {
+        return $this->fields['customerId'];
+    }
+
+    public function setCustomerId(string $customerId): static
+    {
+        $this->fields['customerId'] = $customerId;
+
+        return $this;
+    }
+
+    public function getStrategyId(): ?string
+    {
+        return $this->fields['strategyId'] ?? null;
+    }
+
+    public function setStrategyId(null|string $strategyId): static
+    {
+        $this->fields['strategyId'] = $strategyId;
+
+        return $this;
+    }
+
+    public function getCurrency(): string
+    {
+        return $this->fields['currency'];
+    }
+
+    public function setCurrency(string $currency): static
+    {
+        $this->fields['currency'] = $currency;
+
+        return $this;
+    }
+
+    /**
+     * @return null|float[]
+     */
+    public function getAmounts(): ?array
+    {
+        return $this->fields['amounts'] ?? null;
+    }
+
+    /**
+     * @param null|float[] $amounts
+     */
+    public function setAmounts(null|array $amounts): static
+    {
+        $amounts = $amounts !== null ? array_map(
+            fn ($value) => $value,
+            $amounts,
+        ) : null;
+
+        $this->fields['amounts'] = $amounts;
+
+        return $this;
+    }
+
+    public function getCustomAmount(): ?CashierRequestCustomAmount
+    {
+        return $this->fields['customAmount'] ?? null;
+    }
+
+    public function setCustomAmount(null|CashierRequestCustomAmount|array $customAmount): static
+    {
+        if ($customAmount !== null && !($customAmount instanceof CashierRequestCustomAmount)) {
+            $customAmount = CashierRequestCustomAmount::from($customAmount);
+        }
+
+        $this->fields['customAmount'] = $customAmount;
+
+        return $this;
+    }
+
+    public function getRedirectUrl(): ?string
+    {
+        return $this->fields['redirectUrl'] ?? null;
+    }
+
+    public function setRedirectUrl(null|string $redirectUrl): static
+    {
+        $this->fields['redirectUrl'] = $redirectUrl;
+
+        return $this;
+    }
+
+    public function getExpirationTime(): ?DateTimeImmutable
+    {
+        return $this->fields['expirationTime'] ?? null;
+    }
+
+    public function setExpirationTime(null|DateTimeImmutable|string $expirationTime): static
+    {
+        if ($expirationTime !== null && !($expirationTime instanceof DateTimeImmutable)) {
+            $expirationTime = new DateTimeImmutable($expirationTime);
+        }
+
+        $this->fields['expirationTime'] = $expirationTime;
+
+        return $this;
+    }
+
+    public function getCustomPropertySetId(): ?string
+    {
+        return $this->fields['customPropertySetId'] ?? null;
+    }
+
+    public function setCustomPropertySetId(null|string $customPropertySetId): static
+    {
+        $this->fields['customPropertySetId'] = $customPropertySetId;
+
+        return $this;
+    }
+
+    public function jsonSerialize(): array
+    {
+        $data = [];
+        if (array_key_exists('websiteId', $this->fields)) {
+            $data['websiteId'] = $this->fields['websiteId'];
+        }
+        if (array_key_exists('customerId', $this->fields)) {
+            $data['customerId'] = $this->fields['customerId'];
+        }
+        if (array_key_exists('strategyId', $this->fields)) {
+            $data['strategyId'] = $this->fields['strategyId'];
+        }
+        if (array_key_exists('currency', $this->fields)) {
+            $data['currency'] = $this->fields['currency'];
+        }
+        if (array_key_exists('amounts', $this->fields)) {
+            $data['amounts'] = $this->fields['amounts'];
+        }
+        if (array_key_exists('customAmount', $this->fields)) {
+            $data['customAmount'] = $this->fields['customAmount']?->jsonSerialize();
+        }
+        if (array_key_exists('redirectUrl', $this->fields)) {
+            $data['redirectUrl'] = $this->fields['redirectUrl'];
+        }
+        if (array_key_exists('expirationTime', $this->fields)) {
+            $data['expirationTime'] = $this->fields['expirationTime']?->format(DateTimeInterface::RFC3339);
+        }
+        if (array_key_exists('customPropertySetId', $this->fields)) {
+            $data['customPropertySetId'] = $this->fields['customPropertySetId'];
+        }
+
+        return $data;
+    }
+}
diff --git a/src/Model/PlanTrial.php b/src/Model/TrialOnlyPlanTrial.php
similarity index 97%
rename from src/Model/PlanTrial.php
rename to src/Model/TrialOnlyPlanTrial.php
index 32b40b298..c2afbe7ba 100644
--- a/src/Model/PlanTrial.php
+++ b/src/Model/TrialOnlyPlanTrial.php
@@ -15,7 +15,7 @@
 
 use JsonSerializable;
 
-class PlanTrial implements JsonSerializable
+class TrialOnlyPlanTrial implements JsonSerializable
 {
     private array $fields = [];