Added value: +{
+  "description": "PNG picture of the piece (postcard front and back, or the letter's first page) to show the user",
+  "type": "string"
+}

Previous value: -"USPS Certified Mail. \"certified\" ($14.99): tracking number and proof of mailing and delivery. \"certified_return_receipt\" ($19.99): adds the recipient's signature as proof of delivery, which landlords, courts and agencies often require. \"none\" ($4.99): regular First-Class."New value: +"USPS Certified Mail. \"certified\": tracking number and proof of mailing and delivery. \"certified_return_receipt\": adds the recipient's signature as proof of delivery, which landlords, courts and agencies often require. \"none\": regular First-Class. Prices: get_pricing."

Previous value: -"The letter text and font"New value: +"The letter: body text (optionally with a photo) or your own PDF"

Previous value: -"Full letter text. Plain text; blank lines separate paragraphs."New value: +"Full letter text. Plain text; blank lines separate paragraphs. Use this OR pdf_url."

Added value: +{
+  "description": "PDF letters only: print in color (costs a little more; see get_pricing). Text letters print in color automatically when they include image_url.",
+  "type": "boolean"
+}

Previous value: -"Typeface for the letter body"New value: +"Typeface for the letter body (text letters)"

Previous value: -"Optional photo printed at the top of the letter (https JPG or PNG). A letter with a photo prints in color, for a small surcharge (see get_pricing)."New value: +"Text letters only: optional photo printed at the top (https JPG or PNG). A letter with a photo prints in color, for a small surcharge (see get_pricing)."

Added value: +{
+  "description": "Set by Sendpaper: page count of the PDF",
+  "maximum": 9007199254740991,
+  "minimum": -9007199254740991,
+  "type": "integer"
+}

Added value: +{
+  "description": "Mail your own document instead of body text: a public https link to a PDF (up to 6 pages). Pages are fitted to 8.5×11 and a blank address page is added in front.",
+  "maxLength": 2000,
+  "type": "string"
+}

Removed value: -[
-  "body"
-]

Added value: +{
+  "default": false,
+  "description": "Send by express (USPS Priority Mail, usually 2–3 days, with tracking) for an extra charge; see get_pricing. Not available with certified.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Send the same piece to several people: 2-25 US addresses, used INSTEAD of to. Each gets their own order and tracking; one payment covers all.",
+  "items": {
+    "properties": {
+      "city": {
+        "description": "City",
+        "maxLength": 40,
+        "minLength": 2,
+        "type": "string"
+      },
+      "company": {
+        "description": "Company name, printed under the person's name",
+        "maxLength": 60,
+        "type": "string"
+      },
+      "line1": {
+        "description": "Street address",
+        "maxLength": 64,
+        "minLength": 3,
+        "type": "string"
+      },
+      "line2": {
+        "description": "Apartment, suite, unit",
+        "maxLength": 64,
+        "type": "string"
+      },
+      "name": {
+        "description": "Recipient or sender full name",
+        "maxLength": 60,
+        "minLength": 1,
+        "type": "string"
+      },
+      "state": {
+        "description": "Two-letter US state code, e.g. NY",
+        "type": "string"
+      },
+      "zip": {
+        "description": "5-digit US ZIP code, or ZIP+4",
+        "pattern": "^\\d{5}(-\\d{4})?$",
+        "type": "string"
+      }
+    },
+    "required": [
+      "name",
+      "line1",
+      "city",
+      "state",
+      "zip"
+    ],
+    "type": "object"
+  },
+  "maxItems": 25,
+  "minItems": 2,
+  "type": "array"
+}

Previous value: -"Recipient's US mailing address"New value: +"Recipient's US mailing address (or use recipients for several people)"

Previous value: -[
-  "to",
-  "from",
-  "content"
-]New value: +[
+  "from",
+  "content"
+]

Added value: +{
+  "additionalProperties": false,
+  "description": "Present when the order was created with recipients: the whole group. The top-level fields describe the first recipient's order; use batch.price and batch.checkout_url for the total and payment.",
+  "properties": {
+    "checkout_url": {
+      "description": "One payment link for every unpaid order in the group",
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "count": {
+      "description": "How many recipients (one order each)",
+      "type": "number"
+    },
+    "discount": {
+      "anyOf": [
+        {
+          "additionalProperties": false,
+          "properties": {
+            "amount_cents": {
+              "type": "number"
+            },
+            "display": {
+              "type": "string"
+            },
+            "reason": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "amount_cents",
+            "display",
+            "reason"
+          ],
+          "type": "object"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "id": {
+      "type": "string"
+    },
+    "price": {
+      "additionalProperties": false,
+      "description": "Total for the whole group",
+      "properties": {
+        "amount_cents": {
+          "type": "number"
+        },
+        "currency": {
+          "type": "string"
+        },
+        "display": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "amount_cents",
+        "currency",
+        "display"
+      ],
+      "type": "object"
+    },
+    "url": {
+      "description": "Group page listing every recipient",
+      "type": "string"
+    }
+  },
+  "required": [
+    "id",
+    "count",
+    "url",
+    "checkout_url",
+    "price",
+    "discount"
+  ],
+  "type": "object"
+}

Added value: +{
+  "description": "Every order in the group, when created with recipients",
+  "items": {
+    "additionalProperties": false,
+    "properties": {
+      "id": {
+        "type": "string"
+      },
+      "order_url": {
+        "type": "string"
+      },
+      "preview_url": {
+        "type": "string"
+      },
+      "to": {
+        "type": "string"
+      }
+    },
+    "required": [
+      "id",
+      "to",
+      "order_url",
+      "preview_url"
+    ],
+    "type": "object"
+  },
+  "type": "array"
+}

Added value: +{
+  "description": "Optional photo printed at the top of the letter (https JPG or PNG). A letter with a photo prints in color, for a small surcharge (see get_pricing).",
+  "maxLength": 2000,
+  "type": "string"
+}

Added value: +{
+  "anyOf": [
+    {
+      "additionalProperties": false,
+      "properties": {
+        "amount_cents": {
+          "type": "number"
+        },
+        "display": {
+          "type": "string"
+        },
+        "reason": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "amount_cents",
+        "display",
+        "reason"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "description": "First-order discount, already taken off price; null when none applies"
+}

Removed value: -{
-  "additionalProperties": false,
-  "description": "Present when the first-postcard-free offer applies",
-  "properties": {
-    "applied": {
-      "type": "boolean"
-    },
-    "eligible": {
-      "type": "boolean"
-    },
-    "how": {
-      "type": "string"
-    }
-  },
-  "type": "object"
-}

Previous value: -[
-  "id",
-  "object",
-  "product",
-  "product_name",
-  "certified",
-  "status",
-  "status_detail",
-  "price",
-  "checkout_url",
-  "order_url",
-  "preview_url",
-  "tracking"
-]New value: +[
+  "id",
+  "object",
+  "product",
+  "product_name",
+  "certified",
+  "status",
+  "status_detail",
+  "price",
+  "checkout_url",
+  "order_url",
+  "preview_url",
+  "tracking",
+  "discount"
+]

Added value: +"The letter text and font"

Added value: +"Typeface for the letter body"

Added value: +"City"

Added value: +"Company name, printed under the person's name"

Added value: +"Two-letter US state code, e.g. NY"

Added value: +"5-digit US ZIP code, or ZIP+4"

Added value: +"Any unique string; retrying with the same key returns the original order instead of creating a duplicate"

Added value: +"Recipient's US mailing address"

Added value: +"City"

Added value: +"Company name, printed under the person's name"

Added value: +"Two-letter US state code, e.g. NY"

Added value: +"5-digit US ZIP code, or ZIP+4"

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": {},
+  "properties": {
+    "certified": {
+      "description": "none, certified or certified_return_receipt",
+      "type": "string"
+    },
+    "checkout_url": {
+      "description": "Where the user pays; null once paid or cancelled",
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "first_postcard_free": {
+      "additionalProperties": false,
+      "description": "Present when the first-postcard-free offer applies",
+      "properties": {
+        "applied": {
+          "type": "boolean"
+        },
+        "eligible": {
+          "type": "boolean"
+        },
+        "how": {
+          "type": "string"
+        }
+      },
+      "type": "object"
+    },
+    "id": {
+      "description": "Order id, ord_…",
+      "type": "string"
+    },
+    "object": {
+      "enum": [
+        "postcard",
+        "letter"
+      ],
+      "type": "string"
+    },
+    "order_url": {
+      "description": "Order status page",
+      "type": "string"
+    },
+    "preview_url": {
+      "description": "Exact print preview",
+      "type": "string"
+    },
+    "price": {
+      "additionalProperties": false,
+      "properties": {
+        "amount_cents": {
+          "type": "number"
+        },
+        "currency": {
+          "type": "string"
+        },
+        "display": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "amount_cents",
+        "currency",
+        "display"
+      ],
+      "type": "object"
+    },
+    "product": {
+      "description": "Product id, e.g. postcard_4x6 or letter_certified",
+      "type": "string"
+    },
+    "product_name": {
+      "type": "string"
+    },
+    "status": {
+      "description": "awaiting_payment, paid, printing, mailed, cancelled or refunded",
+      "type": "string"
+    },
+    "status_detail": {
+      "description": "Plain-English status to show the user",
+      "type": "string"
+    },
+    "tracking": {
+      "anyOf": [
+        {
+          "additionalProperties": false,
+          "properties": {
+            "number": {
+              "type": "string"
+            },
+            "url": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "number",
+            "url"
+          ],
+          "type": "object"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "description": "USPS tracking, for Certified Mail once printed"
+    }
+  },
+  "required": [
+    "id",
+    "object",
+    "product",
+    "product_name",
+    "certified",
+    "status",
+    "status_detail",
+    "price",
+    "checkout_url",
+    "order_url",
+    "preview_url",
+    "tracking"
+  ],
+  "type": "object"
+}

Added value: +{
+  "default": "none",
+  "description": "USPS Certified Mail. \"certified\" ($14.99): tracking number and proof of mailing and delivery. \"certified_return_receipt\" ($19.99): adds the recipient's signature as proof of delivery, which landlords, courts and agencies often require. \"none\" ($4.99): regular First-Class.",
+  "enum": [
+    "none",
+    "certified",
+    "certified_return_receipt"
+  ],
+  "type": "string"
+}