diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 3310906..f138fe3 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -7,7 +7,7 @@ jobs:
     timeout-minutes: 10
     strategy:
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
 
     steps:
       - name: Checkout repository code
diff --git a/.gitignore b/.gitignore
index fc3d917..166e1c7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -35,5 +35,6 @@ nosetests.xml
 .pydevproject
 
 .idea/
+.venv/
 venv/
 .DS_Store
diff --git a/README.md b/README.md
index a32e82b..e0f1256 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 quantile-estimator
 ==========================
 
-Python Implementation of Graham Cormode and S. Muthukrishnan's Effective Computation of Biased Quantiles over Data Streams in ICDE’05
+Python Implementation of Graham Cormode and S. Muthukrishnan's Effective Computation of Biased Quantiles over Data Streams in ICDE'05
 
 ## Installation
 ```
diff --git a/quantile_estimator/__init__.py b/quantile_estimator/__init__.py
index a959f83..c4beb84 100644
--- a/quantile_estimator/__init__.py
+++ b/quantile_estimator/__init__.py
@@ -225,6 +225,7 @@ def __init__(self, *invariants, max_age_seconds=10 * 60, age_buckets=5):
 
         # needed for original aioprometheus Summary metric
         # https://github.com/claws/aioprometheus
+        # TODO: probably need to drop it, as aioprometheus project looks abandoned
         self._observations = 0
         self._sum = 0
         self._invariants = self.ring_buckets[0]._invariants
diff --git a/setup.py b/setup.py
index 2324302..3da9ac5 100644
--- a/setup.py
+++ b/setup.py
@@ -26,10 +26,17 @@ def readfile(filename) -> str:
     packages=["quantile_estimator"],
     platforms="Platform Independent",
     classifiers=[
-        "Development Status :: 3 - Alpha",
+        "Development Status :: 4 - Beta",
         "Intended Audience :: Developers",
         "License :: OSI Approved :: Apache Software License",
         "Operating System :: OS Independent",
         "Topic :: Scientific/Engineering :: Mathematics",
+        "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
+        "Programming Language :: Python :: 3.11",
+        "Programming Language :: Python :: 3.12",
+        "Programming Language :: Python :: 3.13",
     ],
 )
diff --git a/tests/test_estimator.py b/tests/test_estimator.py
index 744d736..71dd8c5 100644
--- a/tests/test_estimator.py
+++ b/tests/test_estimator.py
@@ -15,7 +15,7 @@ def test_random_observations(num_observations):
 
 
 def test_border_invariants():
-    estimator = Estimator((0.0, 0.), (1.0, 0.))
+    estimator = Estimator((0.0, 0.0), (1.0, 0.0))
 
     values = [random.randint(1, 1000) for _ in range(1000)]
     for x in values: