diff --git a/18.md b/18.md
index 34571360f..64fa2cdae 100644
--- a/18.md
+++ b/18.md
@@ -24,6 +24,7 @@ A Payment Request is defined as follows
   "u": str <optional>,
   "s": bool <optional>,
   "m": Array[str] <optional>,
+  "ms": bool <optional>,
   "d": str <optional>,
   "t": Array[Transport] <optional>,
   "nut10": NUT10Option <optional>,
@@ -37,10 +38,15 @@ Here, the fields are
 - `u`: The unit of the requested payment (MUST be set if `a` is set)
 - `s`: Whether the payment request is for single use
 - `m`: A set of mints from which the payment is requested
+- `ms`: A flag indicating whether the mint list is strict; defaults to `true`
 - `d`: A human readable description that the sending wallet will display after scanning the request
 - `t`: The method of `Transport` chosen to transmit the payment (can be multiple, sorted by preference)
 - `nut10`: The required [NUT-10][10] locking condition
 
+## Mint list
+
+A Payment Request containing a mint list `m` describes the mints it accepts payments from. If `ms` is not present, or is `true`, the recipient **MUST** reject payments from mints not in the list. If `ms` is set to `false`, the list is just a suggestion for the payer.
+
 ## Locking conditions
 
 The payment request can include _optional_ locking conditions the payee requires from the payer. For example, the payee might require a P2PK-locked token so that they can receive payments offline.
diff --git a/26.md b/26.md
index 555d8bcf7..57ab38550 100644
--- a/26.md
+++ b/26.md
@@ -33,16 +33,17 @@ The payment request is encoded as a sequence of TLV fields. Each TLV entry consi
 
 ### Top-Level TLV Tags
 
-| Tag  | Field       | Type      | Description                                                          |
-| ---- | ----------- | --------- | -------------------------------------------------------------------- |
-| 0x01 | id          | string    | Payment identifier (corresponds to `i` in JSON)                      |
-| 0x02 | amount      | u64       | Amount in base units (corresponds to `a` in JSON)                    |
-| 0x03 | unit        | u8/string | Currency unit (corresponds to `u` in JSON)                           |
-| 0x04 | single_use  | u8        | Single-use flag: 0=false, 1=true (corresponds to `s` in JSON)        |
-| 0x05 | mint        | string    | Mint URL (repeatable for multiple mints, corresponds to `m` in JSON) |
-| 0x06 | description | string    | Human-readable description (corresponds to `d` in JSON)              |
-| 0x07 | transport   | sub-TLV   | Transport configuration (repeatable, corresponds to `t` in JSON)     |
-| 0x08 | nut10       | sub-TLV   | NUT-10 spending conditions (corresponds to `nut10` in JSON)          |
+| Tag  | Field       | Type      | Description                                                                                    |
+| ---- | ----------- | --------- | ---------------------------------------------------------------------------------------------- |
+| 0x01 | id          | string    | Payment identifier (corresponds to `i` in JSON)                                                |
+| 0x02 | amount      | u64       | Amount in base units (corresponds to `a` in JSON)                                              |
+| 0x03 | unit        | u8/string | Currency unit (corresponds to `u` in JSON)                                                     |
+| 0x04 | single_use  | u8        | Single-use flag: 0=false, 1=true (corresponds to `s` in JSON)                                  |
+| 0x05 | mint        | string    | Mint URL (repeatable for multiple mints, corresponds to `m` in JSON)                           |
+| 0x06 | description | string    | Human-readable description (corresponds to `d` in JSON)                                        |
+| 0x07 | transport   | sub-TLV   | Transport configuration (repeatable, corresponds to `t` in JSON)                               |
+| 0x08 | nut10       | sub-TLV   | NUT-10 spending conditions (corresponds to `nut10` in JSON)                                    |
+| 0x09 | mint_strict | u8        | Mint list strict flag: 0=false, 1=true; if absent, defaults to 1 (corresponds to `ms` in JSON) |
 
 All fields are optional. Unknown tags MUST be ignored to maintain forward compatibility.