diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9b8af4b..7b0d446 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -24,7 +24,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        python-version: ['3.10']
+        python-version: ['3.11']
 
     steps:
     - uses: actions/checkout@v6
@@ -37,13 +37,13 @@ jobs:
     - name: Install Hatch
       run: pip install --upgrade hatch
 
-    - if: matrix.python-version == '3.10' && runner.os == 'Linux'
+    - if: matrix.python-version == '3.11' && runner.os == 'Linux'
       name: Lint
       run: hatch run lint:all
 
     - name: Run tests and track code coverage
       run: hatch run cov
-    - if: matrix.python-version == '3.10' && runner.os == 'Linux'
+    - if: matrix.python-version == '3.11' && runner.os == 'Linux'
       name: Publish Coverage to Coveralls
       run: hatch run coveralls
       env:
@@ -56,10 +56,10 @@ jobs:
     steps:
     - uses: actions/checkout@v6
 
-    - name: Set up Python 3.10
+    - name: Set up Python 3.11
       uses: actions/setup-python@v6
       with:
-        python-version: '3.10'
+        python-version: '3.11'
 
     - name: Install Hatch
       run: pip install --upgrade hatch hatch-containers
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7d14d55..f783f1a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## Release `3.0.0` - 2026-10-18
+
+* **Breaking**: Drop support for Python 3.10, which reached end-of-life in October 2026. Minimum required version is now Python 3.11.
+* Add Python 3.15 to supported versions.
+
 ## Release `2.0.1` - 2026-03-11
 
 * Bugfix: `get_symbols_v2()`, `get_sp500_companies_txt_file()`, `get_events()`, and `get_exchanges_json()` now raise `HTTPError` on failed API responses instead of silently returning the raw response. Previously, non-200 responses were passed through to callers, which would then crash with `AttributeError` (e.g., calling `.split()` on a non-text response) or return corrupt data.
diff --git a/CLAUDE.md b/CLAUDE.md
index 3f6bc38..57037a8 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -40,7 +40,7 @@ vars, defaulting to `"demo"` (AAPL-only sample access; other symbols raise
 - Build/test/lint via Hatch (hatchling backend) — commands in
   [DEVELOPMENT.md](DEVELOPMENT.md). CI (`.github/workflows/test.yml`) runs
   `hatch run lint:all` (ruff, black, mypy), `hatch run cov` (Coveralls), and a
-  containerized matrix `hatch run all:test` on Python 3.10–3.14.
+  containerized matrix `hatch run all:test` on Python 3.11–3.15.
 - Releases: bump the static `version` in `pyproject.toml` `[project]`, add a
   `## Release \`X.Y.Z\` - YYYY-MM-DD` entry to `CHANGELOG.md`, then push a
   `vX.Y.Z` tag. `.github/workflows/release.yml` builds and publishes to PyPI
diff --git a/README.md b/README.md
index 441f090..7f8eb77 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ responses.
 
 # Requirements
 
-* Python 3.10+
+* Python 3.11+
 
 # Installation
 
diff --git a/earningscall/api.py b/earningscall/api.py
index 20fa4aa..ea3cc91 100644
--- a/earningscall/api.py
+++ b/earningscall/api.py
@@ -141,6 +141,7 @@ def do_get(
     delay = retry_strategy["base_delay"]
     max_attempts = int(retry_strategy["max_attempts"])
 
+    response: requests.Response
     for attempt in range(max_attempts):
         if use_cache and earningscall.enable_requests_cache:
             response = cache_session().get(url, params=params)
diff --git a/earningscall/event.py b/earningscall/event.py
index 688597f..b9da223 100644
--- a/earningscall/event.py
+++ b/earningscall/event.py
@@ -14,9 +14,6 @@ def _parse_conference_date(date_str: str) -> Optional[datetime]:
     """Parse conference date string, handling both timezone offsets and 'Z' UTC suffix."""
     if not date_str:
         return None
-    # Handle 'Z' suffix by converting to '+00:00' for UTC
-    if date_str.endswith('Z'):
-        date_str = date_str[:-1] + '+00:00'
     return datetime.fromisoformat(date_str)
 
 
diff --git a/hatch.toml b/hatch.toml
index 596a635..c8f7716 100644
--- a/hatch.toml
+++ b/hatch.toml
@@ -21,7 +21,7 @@ cov = [
 type = "container"
 
 [[envs.all.matrix]]
-python = ["3.10", "3.11", "3.12", "3.13", "3.14"]
+python = ["3.11", "3.12", "3.13", "3.14", "3.15"]
 
 [envs.lint]
 detached = true
diff --git a/pyproject.toml b/pyproject.toml
index 840831b..d146bfc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,10 +1,10 @@
 [project]
 name = "earningscall"
-version = "2.0.1"
+version = "3.0.0"
 description = "The EarningsCall Python library provides convenient access to the EarningsCall API.  It includes a pre-defined set of classes for API resources that initialize themselves dynamically from API responses."
 readme = "README.md"
 authors = [{ name = "EarningsCall", email = "dev@earningscall.biz" }]
-requires-python = ">= 3.10"
+requires-python = ">= 3.11"
 dependencies = [
   "dataclasses-json>=0.6.4",
   "requests>=2.30.0",
@@ -42,11 +42,11 @@ classifiers = [
 
   # Specify the Python versions you support here.
   "Programming Language :: Python :: 3",
-  "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
   "Programming Language :: Python :: 3.14",
+  "Programming Language :: Python :: 3.15",
 ]
 
 [project.urls]
@@ -79,7 +79,7 @@ cov = "pytest --cov-report=term-missing --cov-config=pyproject.toml --cov=hatch_
 no-cov = "cov --no-cov"
 
 [[tool.hatch.envs.test.matrix]]
-python = ["3.10", "3.11", "3.12", "3.13", "3.14"]
+python = ["3.11", "3.12", "3.13", "3.14", "3.15"]
 
 
 [tool.hatch.build.targets.wheel.hooks.mypyc]
@@ -99,14 +99,17 @@ warn_unused_ignores = true
 
 
 [tool.black]
-target-version = ["py310"]
+target-version = ["py311"]
 line-length = 120
 skip-string-normalization = true
 
 [tool.ruff]
-target-version = "py310"
+target-version = "py311"
 
 [tool.ruff.lint]
+# Pin the rule set explicitly. Ruff 0.16 expanded its default selection, which
+# broke CI without any code change.
+select = ["E4", "E7", "E9", "F"]
 ignore = [
   # Allow non-abstract empty methods in abstract base classes
   "B027",