diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6b33ac6..c464656 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## [2.1.2]
+### Fixed
+- Point at infinity handling in C extensions
+- DER signature decoding that assumed length was always encoded in one byte
+
 ## [2.1.1]
 ### Fixed
 - RFC6979 nonce generation for signatures on pre-hashed messages (issue #46)
diff --git a/fastecdsa/encoding/asn1.py b/fastecdsa/encoding/asn1.py
index a865f81..2596011 100644
--- a/fastecdsa/encoding/asn1.py
+++ b/fastecdsa/encoding/asn1.py
@@ -99,8 +99,8 @@ def parse_asn1_length(data: bytes) -> (int, bytes, bytes):
         data = data[count:]
 
     if length > len(data):
-        raise ASN1EncodingError(f"Parsed length of ASN.1 structure to be {length} bytes but only {len(data)} bytes"
-                                f"remain in the provided data")
+        raise ASN1EncodingError("Parsed length of ASN.1 structure to be {} bytes but only {} bytes"
+                                "remain in the provided data".format(length, len(data)))
 
     return length, data[:length], data[length:]
 
@@ -128,6 +128,6 @@ def parse_asn1_int(data: bytes) -> (int, bytes, bytes):
 
     # integer length should match length indicated
     if length != len(data):
-        raise ASN1EncodingError(f"Expected ASN.1 INTEGER to be {length} bytes, got {len(data)} bytes")
+        raise ASN1EncodingError("Expected ASN.1 INTEGER to be {} bytes, got {} bytes".format(length, len(data)))
 
     return length, data, remaining
diff --git a/fastecdsa/encoding/der.py b/fastecdsa/encoding/der.py
index ac0ba3d..7dd545a 100644
--- a/fastecdsa/encoding/der.py
+++ b/fastecdsa/encoding/der.py
@@ -60,7 +60,8 @@ def _validate_int_bytes(data: bytes):
 
         # sequence should be entirety remaining data
         if leftover:
-            raise InvalidDerSignature(f"Expected a sequence of {seqlen} bytes, got {len(sequence + leftover)}")
+            raise InvalidDerSignature("Expected a sequence of {} bytes, got {}".format(
+                seqlen, len(sequence + leftover)))
 
         try:
             rlen, r, sdata = parse_asn1_int(sequence)
diff --git a/fastecdsa/tests/test_whycheproof_vectors.py b/fastecdsa/tests/test_whycheproof_vectors.py
index 1effe10..a44e298 100644
--- a/fastecdsa/tests/test_whycheproof_vectors.py
+++ b/fastecdsa/tests/test_whycheproof_vectors.py
@@ -23,7 +23,7 @@ def _get_tests(url):
             test_json = loads(test_raw)
             return test_json["testGroups"]
         except (JSONDecodeError, URLError) as error:
-            SkipTest(f"Skipping tests, could not download / parse data from {url}\nError: {error}")
+            SkipTest("Skipping tests, could not download / parse data from {}\nError: {}".format(url, error))
 
     def _test_runner(self, tests, curve, hashfunc):
         for test_group in tests:
diff --git a/setup.py b/setup.py
index 35a7eb3..d8a86a6 100644
--- a/setup.py
+++ b/setup.py
@@ -57,5 +57,5 @@ def run(self):
     name='fastecdsa',
     packages=find_packages(),
     url='https://github.com/AntonKueltz/fastecdsa',
-    version='2.1.1',
+    version='2.1.2',
 )