diff --git a/cashu/mint/app.py b/cashu/mint/app.py
index f0a6b73..9853598 100644
--- a/cashu/mint/app.py
+++ b/cashu/mint/app.py
@@ -2,13 +2,19 @@ import asyncio
 import logging
 import sys
 
-from fastapi import FastAPI
+from fastapi import FastAPI, Request
 from loguru import logger
 
 from cashu.core.settings import DEBUG, VERSION
 from cashu.lightning import WALLET
 from cashu.mint.migrations import m001_initial
 
+from starlette_context.middleware import RawContextMiddleware
+from starlette_context import context
+from starlette.middleware import Middleware
+from starlette.requests import Request as StarletteRequest
+
+
 from . import ledger
 from .router import router
 from .startup import load_ledger
@@ -49,6 +55,15 @@ def create_app(config_object="core.settings") -> FastAPI:
 
     configure_logger()
 
+    middleware = [
+        Middleware(
+            RawContextMiddleware,
+        ),
+        Middleware(
+            RawContextMiddleware,
+        ),
+    ]
+
     app = FastAPI(
         title="Cashu Mint",
         description="Ecash wallet and mint with Bitcoin Lightning support.",
@@ -57,8 +72,8 @@ def create_app(config_object="core.settings") -> FastAPI:
             "name": "MIT License",
             "url": "https://raw.githubusercontent.com/callebtc/cashu/main/LICENSE",
         },
+        middleware=middleware,
     )
-
     return app
 
 
diff --git a/cashu/mint/ledger.py b/cashu/mint/ledger.py
index 1cbb93c..2f02139 100644
--- a/cashu/mint/ledger.py
+++ b/cashu/mint/ledger.py
@@ -7,6 +7,7 @@ from typing import Dict, List, Set
 
 from loguru import logger
 
+import cashu.core.legacy as legacy
 import cashu.core.b_dhke as b_dhke
 import cashu.core.bolt11 as bolt11
 from cashu.core.base import (
@@ -36,6 +37,8 @@ from cashu.mint.crud import (
     update_lightning_invoice,
 )
 
+from starlette_context import context
+
 
 class Ledger:
     def __init__(self, secret_key: str, db: str, derivation_path=""):
@@ -113,6 +116,9 @@ class Ledger:
 
         C = PublicKey(bytes.fromhex(proof.C), raw=True)
 
+        # backwards compatibility with old hash_to_curve
+        if not context.get("version"):
+            return legacy.verify_pre_0_3_3(secret_key, C, proof.secret)
         return b_dhke.verify(secret_key, C, proof.secret)
 
     def _verify_script(self, idx: int, proof: Proof):
diff --git a/cashu/mint/router.py b/cashu/mint/router.py
index 260d8bd..8d95062 100644
--- a/cashu/mint/router.py
+++ b/cashu/mint/router.py
@@ -20,6 +20,10 @@ from cashu.mint import ledger
 router: APIRouter = APIRouter()
 
 
+from starlette.requests import Request
+from starlette_context import context
+
+
 @router.get("/keys")
 def keys():
     """Get the public keys of the mint"""
@@ -49,7 +53,6 @@ async def request_mint(amount: int = 0):
 @router.post("/mint")
 async def mint(
     payloads: MintRequest,
-    bolt11: Union[str, None] = None,
     payment_hash: Union[str, None] = None,
 ):
     """
@@ -70,10 +73,12 @@ async def mint(
 
 
 @router.post("/melt")
-async def melt(payload: MeltRequest):
+async def melt(request: Request, payload: MeltRequest):
     """
     Requests tokens to be destroyed and sent out via Lightning.
     """
+    context["version"] = request.headers.get("Client-version")
+    print(context["version"])
     ok, preimage = await ledger.melt(payload.proofs, payload.invoice)
     resp = GetMeltResponse(paid=ok, preimage=preimage)
     return resp
@@ -97,11 +102,13 @@ async def check_fees(payload: CheckFeesRequest):
 
 
 @router.post("/split")
-async def split(payload: SplitRequest):
+async def split(request: Request, payload: SplitRequest):
     """
     Requetst a set of tokens with amount "total" to be split into two
     newly minted sets with amount "split" and "total-split".
     """
+    context["version"] = request.headers.get("Client-version")
+    print(context["version"])
     proofs = payload.proofs
     amount = payload.amount
     outputs = payload.outputs.blinded_messages if payload.outputs else None
diff --git a/cashu/wallet/wallet.py b/cashu/wallet/wallet.py
index 1ba984e..8c95034 100644
--- a/cashu/wallet/wallet.py
+++ b/cashu/wallet/wallet.py
@@ -30,7 +30,7 @@ from cashu.core.script import (
     step2_carol_sign_tx,
 )
 from cashu.core.secp import PublicKey
-from cashu.core.settings import DEBUG
+from cashu.core.settings import DEBUG, VERSION
 from cashu.core.split import amount_split
 from cashu.wallet.crud import (
     get_keyset,
@@ -52,7 +52,10 @@ class LedgerAPI:
         self.url = url
 
     async def _get_keys(self, url):
-        resp = requests.get(url + "/keys").json()
+        resp = requests.get(
+            url + "/keys",
+            headers={"Client-version": VERSION},
+        ).json()
         keys = resp
         assert len(keys), Exception("did not receive any keys")
         keyset_keys = {
@@ -63,7 +66,10 @@ class LedgerAPI:
         return keyset
 
     async def _get_keysets(self, url):
-        keysets = requests.get(url + "/keysets").json()
+        keysets = requests.get(
+            url + "/keysets",
+            headers={"Client-version": VERSION},
+        ).json()
         assert len(keysets), Exception("did not receive any keysets")
         return keysets
 
@@ -177,6 +183,7 @@ class LedgerAPI:
             self.url + "/mint",
             json=payloads.dict(),
             params={"payment_hash": payment_hash},
+            headers={"Client-version": VERSION},
         )
         resp.raise_for_status()
         try:
@@ -235,6 +242,7 @@ class LedgerAPI:
         resp = requests.post(
             self.url + "/split",
             json=split_payload.dict(include=_splitrequest_include_fields(proofs)),
+            headers={"Client-version": VERSION},
         )
         resp.raise_for_status()
         try:
@@ -260,6 +268,7 @@ class LedgerAPI:
         resp = requests.post(
             self.url + "/check",
             json=payload.dict(),
+            headers={"Client-version": VERSION},
         )
         resp.raise_for_status()
         return_dict = resp.json()
@@ -272,6 +281,7 @@ class LedgerAPI:
         resp = requests.post(
             self.url + "/checkfees",
             json=payload.dict(),
+            headers={"Client-version": VERSION},
         )
         resp.raise_for_status()
 
@@ -293,6 +303,7 @@ class LedgerAPI:
         resp = requests.post(
             self.url + "/melt",
             json=payload.dict(include=_meltequest_include_fields(proofs)),
+            headers={"Client-version": VERSION},
         )
         resp.raise_for_status()
 
diff --git a/poetry.lock b/poetry.lock
index 7d8c34d..546c59b 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -167,7 +167,7 @@ starlette = "0.19.1"
 [package.extras]
 all = ["email_validator (>=1.1.1,<2.0.0)", "itsdangerous (>=1.1.0,<3.0.0)", "jinja2 (>=2.11.2,<4.0.0)", "orjson (>=3.2.1,<4.0.0)", "python-multipart (>=0.0.5,<0.0.6)", "pyyaml (>=5.3.1,<7.0.0)", "requests (>=2.24.0,<3.0.0)", "ujson (>=4.0.1,!=4.0.2,!=4.1.0,!=4.2.0,!=4.3.0,!=5.0.0,!=5.1.0,<6.0.0)", "uvicorn[standard] (>=0.12.0,<0.18.0)"]
 dev = ["autoflake (>=1.4.0,<2.0.0)", "flake8 (>=3.8.3,<6.0.0)", "passlib[bcrypt] (>=1.7.2,<2.0.0)", "pre-commit (>=2.17.0,<3.0.0)", "python-jose[cryptography] (>=3.3.0,<4.0.0)", "uvicorn[standard] (>=0.12.0,<0.18.0)"]
-doc = ["mdx-include (>=1.4.1,<2.0.0)", "mkdocs (>=1.1.2,<2.0.0)", "mkdocs-markdownextradata-plugin (>=0.1.7,<0.3.2)", "mkdocs-material (>=8.1.4,<9.0.0)", "pyyaml (>=5.3.1,<7.0.0)", "typer (>=0.4.1,<0.5.0)"]
+doc = ["mdx-include (>=1.4.1,<2.0.0)", "mkdocs (>=1.1.2,<2.0.0)", "mkdocs-markdownextradata-plugin (>=0.1.7,<0.3.0)", "mkdocs-material (>=8.1.4,<9.0.0)", "pyyaml (>=5.3.1,<7.0.0)", "typer (>=0.4.1,<0.5.0)"]
 test = ["anyio[trio] (>=3.2.1,<4.0.0)", "black (==22.3.0)", "databases[sqlite] (>=0.3.2,<0.6.0)", "email_validator (>=1.1.1,<2.0.0)", "flake8 (>=3.8.3,<6.0.0)", "flask (>=1.1.2,<3.0.0)", "httpx (>=0.14.0,<0.19.0)", "isort (>=5.0.6,<6.0.0)", "mypy (==0.910)", "orjson (>=3.2.1,<4.0.0)", "peewee (>=3.13.3,<4.0.0)", "pytest (>=6.2.4,<7.0.0)", "pytest-cov (>=2.12.0,<4.0.0)", "python-multipart (>=0.0.5,<0.0.6)", "requests (>=2.24.0,<3.0.0)", "sqlalchemy (>=1.3.18,<1.5.0)", "types-dataclasses (==0.6.5)", "types-orjson (==3.6.2)", "types-ujson (==4.2.1)", "ujson (>=4.0.1,!=4.0.2,!=4.1.0,!=4.2.0,!=4.3.0,!=5.0.0,!=5.1.0,<6.0.0)"]
 
 [[package]]
@@ -553,6 +553,17 @@ typing-extensions = {version = ">=3.10.0", markers = "python_version < \"3.10\""
 [package.extras]
 full = ["itsdangerous", "jinja2", "python-multipart", "pyyaml", "requests"]
 
+[[package]]
+name = "starlette-context"
+version = "0.3.4"
+description = "Access context in Starlette"
+category = "main"
+optional = false
+python-versions = ">=3.7"
+
+[package.dependencies]
+starlette = "*"
+
 [[package]]
 name = "tomli"
 version = "2.0.1"
@@ -632,7 +643,7 @@ testing = ["func-timeout", "jaraco.itertools", "pytest (>=6)", "pytest-black (>=
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.7"
-content-hash = "b4e980ee90226bab07750b1becc8c69df7752f6d168d200a79c782aa1efe61da"
+content-hash = "14ff9c57ca971c645f1a075b5c6fa0a84a38eaf6399d14afa724136728a3da03"
 
 [metadata.files]
 anyio = [
@@ -999,6 +1010,10 @@ starlette = [
     {file = "starlette-0.19.1-py3-none-any.whl", hash = "sha256:5a60c5c2d051f3a8eb546136aa0c9399773a689595e099e0877704d5888279bf"},
     {file = "starlette-0.19.1.tar.gz", hash = "sha256:c6d21096774ecb9639acad41b86b7706e52ba3bf1dc13ea4ed9ad593d47e24c7"},
 ]
+starlette-context = [
+    {file = "starlette_context-0.3.4-py37-none-any.whl", hash = "sha256:b16bf17bd3ead7ded2f458aebf7f913744b9cf28305e16c69b435a6c6ddf1135"},
+    {file = "starlette_context-0.3.4.tar.gz", hash = "sha256:2d28e1838302fb5d5adacadc10fb73fb2d5cca1f0aa1e279698701cc96f1567c"},
+]
 tomli = [
     {file = "tomli-2.0.1-py3-none-any.whl", hash = "sha256:939de3e7a6161af0c887ef91b7d41a53e7c5a1ca976325f429cb46ea9bc30ecc"},
     {file = "tomli-2.0.1.tar.gz", hash = "sha256:de526c12914f0c550d15924c62d72abc48d6fe7364aa87328337a31007fe8a4f"},
diff --git a/pyproject.toml b/pyproject.toml
index 8eef93e..6b6ce0b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,6 +22,7 @@ bitstring = "^3.1.9"
 secp256k1 = "^0.14.0"
 sqlalchemy-aio = "^0.17.0"
 python-bitcoinlib = "^0.11.2"
+starlette-context = "^0.3.4"
 
 [tool.poetry.dev-dependencies]
 black = {version = "^22.8.0", allow-prereleases = true}