diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index 67b38db..9b508db 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
 
     steps:
     - uses: actions/checkout@v3
diff --git a/README.md b/README.md
index c2255d6..a9a8345 100644
--- a/README.md
+++ b/README.md
@@ -11,17 +11,22 @@ The library features multiple clients for retrieving incidents: a web scraper, a
 ## Example
 
 ```python
-
+import asyncio
 import aiohttp
-from lcwc.feed import Client
+from lcwc.feed import FeedClient
+
+
+async def main():
+    client = FeedClient()
+
+    async with aiohttp.ClientSession() as session:
+        incidents = await client.get_incidents(session)
 
-client = Client()
+        for incident in incidents:
+            print(f'{incident.date} - {incident.description}')
 
-async with aiohttp.ClientSession() as session:
-    incidents = await client.get_incidents(session)
 
-    for incident in incidents:
-        print(f'{incident.date} - {incident.description}')
+asyncio.run(main())
 ```
 
 ## Notes
diff --git a/pyproject.toml b/pyproject.toml
index 43b2248..92f70a8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,23 +1,30 @@
 [project]
 name = "lcwc"
-version = "0.14.0"
+version = "0.15.0"
 authors = [
   { name="Nate Shoffner", email="nate.shoffner@gmail.com" },
 ] 
 description = "Python library for fetching the Lancaster County-Wide Communications live incident list."
 keywords = ["lcwc", "lancaster", "police", "fire", "ems", "dispatch", "911", "incident"]
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 classifiers = [
     "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
 ]
 
 dependencies = [
-    "bs4", 
-    "aiohttp", 
-    "feedparser",
+    "beautifulsoup4",
+    # 3.14.3 is the first release without a known advisory
+    "aiohttp>=3.14.3",
+    # 6.0.11 dropped the cgi import, which python 3.13 removed
+    "feedparser>=6.0.11",
+    "pydantic>=2,<3",
     "pytz"
 ]
 
diff --git a/requirements.txt b/requirements.txt
index a732a3e..4a0e3be 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
-aiohttp==3.10.2
-bs4==0.0.1
-feedparser==6.0.10
+aiohttp==3.14.3
+beautifulsoup4==4.12.2
+feedparser==6.0.14
 pytz
 pydantic
\ No newline at end of file
diff --git a/src/lcwc/__init__.py b/src/lcwc/__init__.py
index 1f3c7c9..d607537 100644
--- a/src/lcwc/__init__.py
+++ b/src/lcwc/__init__.py
@@ -2,7 +2,7 @@
 __author__ = "Nate Shoffner"
 __license__ = "MIT"
 __copyright__ = "Copyright 2023-present Nate Shoffner"
-__version__ = "0.14.0"
+__version__ = "0.15.0"
 
 from .agencies.agency import Agency
 from .agencies.agencyclient import AgencyClient
diff --git a/src/lcwc/agencies/agencyresolver.py b/src/lcwc/agencies/agencyresolver.py
index 1a35da4..1c7b869 100644
--- a/src/lcwc/agencies/agencyresolver.py
+++ b/src/lcwc/agencies/agencyresolver.py
@@ -1,17 +1,17 @@
-import re
+from typing import Optional
+
 from lcwc.agencies import ALL_KNOWN_AGENCIES
 from lcwc.agencies.agency import Agency
-from lcwc.agencies.exceptions import OutOfCountyException, PendingUnitException
 from lcwc.category import IncidentCategory
-from lcwc.incident import Incident
-from lcwc.unit import Unit
 
 
 class AgencyResolver:
     """Collection of dispatch and various lookup methods"""
 
     def __init__(self, load_known: bool = True):
-        self.agencies = ALL_KNOWN_AGENCIES if load_known else []
+        # copy the compiled roster so add_agency/remove_agency only affect this
+        # resolver rather than every resolver in the process
+        self.agencies = list(ALL_KNOWN_AGENCIES) if load_known else []
 
     def add_agency(self, agency: Agency):
         self.agencies.append(agency)
@@ -19,7 +19,9 @@ def add_agency(self, agency: Agency):
     def remove_agency(self, agency: Agency):
         self.agencies.remove(agency)
 
-    def get_agency(self, station_id: str, category: IncidentCategory) -> Agency:
+    def get_agency(
+        self, station_id: str, category: IncidentCategory
+    ) -> Optional[Agency]:
         """Attempts to find the agency associated with the given station id and category within the list of agencies provided"""
         for agency in self.agencies:
             if agency.station_number == station_id and agency.category == category:
@@ -30,11 +32,3 @@ def get_agencies(self, category: IncidentCategory) -> list[Agency]:
 
     def get_all_agencies(self) -> list[Agency]:
         return self.agencies
-
-    def get_unit_agency(self, unit: Unit, category: IncidentCategory) -> Agency:
-        """Attempts to find the agency associated with the given unit and category within the list of agencies provided"""
-
-        if unit.is_shorthand():
-            return self.__unit_short_name_to_agency(unit, category)
-        else:
-            return self.__unit_name_to_agency(unit, category)
diff --git a/src/lcwc/agencies/exceptions.py b/src/lcwc/agencies/exceptions.py
deleted file mode 100644
index 2eb30cd..0000000
--- a/src/lcwc/agencies/exceptions.py
+++ /dev/null
@@ -1,6 +0,0 @@
-class OutOfCountyException(Exception):
-    pass
-
-
-class PendingUnitException(Exception):
-    pass
diff --git a/src/lcwc/arcgis/client.py b/src/lcwc/arcgis/client.py
index 7d6c075..54a7a87 100644
--- a/src/lcwc/arcgis/client.py
+++ b/src/lcwc/arcgis/client.py
@@ -2,10 +2,10 @@
 import aiohttp
 import datetime
 import re
+from typing import Optional
 
 from lcwc import Client
 from lcwc.agencies.agencyresolver import AgencyResolver
-from lcwc.agencies.exceptions import OutOfCountyException, PendingUnitException
 from lcwc.arcgis.incident import ArcGISIncident, Coordinates
 from lcwc.category import IncidentCategory
 from lcwc.unit import Unit
@@ -20,9 +20,11 @@ class ArcGISException(Exception):
 class ArcGISClient(Client):
     """Client for the ArcGIS REST API"""
 
-    def __init__(self, agency_resolver: AgencyResolver = AgencyResolver()) -> None:
+    def __init__(self, agency_resolver: Optional[AgencyResolver] = None) -> None:
         super().__init__()
-        self.agency_resolver = agency_resolver
+        self.agency_resolver = (
+            agency_resolver if agency_resolver is not None else AgencyResolver()
+        )
         self.logger = logging.getLogger(__name__)
 
     @property
diff --git a/src/lcwc/feed/client.py b/src/lcwc/feed/client.py
index a30b761..7aaf3ce 100644
--- a/src/lcwc/feed/client.py
+++ b/src/lcwc/feed/client.py
@@ -1,7 +1,8 @@
+from typing import Optional
+
 import aiohttp
 from lcwc import Client
 from lcwc.agencies.agencyresolver import AgencyResolver
-from lcwc.agencies.exceptions import OutOfCountyException
 
 from lcwc.feed.incident import FeedIncident
 from lcwc.feed.parser import FeedParser
@@ -13,8 +14,10 @@ class FeedClient(Client):
     URL = "https://webcad.lcwc911.us/Pages/Public/LiveIncidentsFeed.aspx"
     """ The URL of the live incident feed """
 
-    def __init__(self, agency_resolver: AgencyResolver = AgencyResolver()) -> None:
-        self.agency_resolver = agency_resolver
+    def __init__(self, agency_resolver: Optional[AgencyResolver] = None) -> None:
+        self.agency_resolver = (
+            agency_resolver if agency_resolver is not None else AgencyResolver()
+        )
         self.parser = FeedParser()
 
     @property
diff --git a/src/lcwc/feed/parser.py b/src/lcwc/feed/parser.py
index c0ee4f9..4972aee 100644
--- a/src/lcwc/feed/parser.py
+++ b/src/lcwc/feed/parser.py
@@ -3,7 +3,6 @@
 import feedparser as FP
 import pytz
 from lcwc.agencies.agencyresolver import AgencyResolver
-from lcwc.agencies.exceptions import OutOfCountyException, PendingUnitException
 from lcwc.feed.incident import FeedIncident
 from lcwc.unit import Unit
 from lcwc.utils.unitparser import UnitParser, UnitParserException
@@ -90,10 +89,6 @@ def has_unit_names(details_segment: str) -> bool:
                 try:
                     u = UnitParser.parse_unit(unit_name, category, agency_resolver)
                     units.append(u)
-                except OutOfCountyException:
-                    self.logger.debug(f"Unit {unit_name} is out of county")
-                except PendingUnitException:
-                    self.logger.debug(f"Unit {unit_name} is pending")
                 except UnitParserException:
                     self.logger.debug(f"Unable to parse unit {unit_name}")
 
diff --git a/src/lcwc/utils/unitconverter.py b/src/lcwc/utils/unitconverter.py
new file mode 100644
index 0000000..82b2f1c
--- /dev/null
+++ b/src/lcwc/utils/unitconverter.py
@@ -0,0 +1,57 @@
+from typing import Optional
+
+
+class UnitConverter:
+    """Converts shorthand unit abbreviations into their long-hand names
+
+    The ArcGIS feed condenses unit names into an abbreviation and an id
+    (ex: "ENG531"), so the abbreviation has to be expanded separately to render
+    a unit the way the web and RSS feeds spell it out.
+    """
+
+    def __init__(self):
+        self.mapping = {
+            # Fire
+            "BRU": "Brush",
+            "DEP": "Deputy",
+            "ENG": "Engine",
+            "RES": "Rescue",
+            "SQU": "Squad",
+            "TAC": "Tactical",
+            "TAN": "Tanker",
+            "TRA": "Tractor",
+            "TRK": "Truck",
+            "UTV": "Utility Vehicle",
+            # Medical
+            "AMB": "Ambulance",
+            "MED": "Medic",
+            "QRS": "Quick Response Service",
+            # Air
+            "AIR": "Air",
+            # Traffic
+            "P": "Police",
+        }
+
+    def register(self, short_hand: str, long_hand: str) -> None:
+        """Registers a shorthand abbreviation, replacing any existing entry
+
+        :param short_hand: The abbreviation as it appears in a unit name
+        :param long_hand: The name the abbreviation expands to
+        """
+        self.mapping[short_hand.upper()] = long_hand
+
+    def unregister(self, short_hand: str) -> None:
+        """Removes a shorthand abbreviation, ignoring unknown ones
+
+        :param short_hand: The abbreviation to remove
+        """
+        self.mapping.pop(short_hand.upper(), None)
+
+    def convert(self, short_hand: str) -> Optional[str]:
+        """Expands the given abbreviation into its long-hand name
+
+        :param short_hand: The abbreviation as it appears in a unit name
+        :return: The long-hand name, or None if the abbreviation is unknown
+        :rtype: Optional[str]
+        """
+        return self.mapping.get(short_hand.upper())
diff --git a/src/lcwc/utils/unitparser.py b/src/lcwc/utils/unitparser.py
index fb85aa1..cd53fe2 100644
--- a/src/lcwc/utils/unitparser.py
+++ b/src/lcwc/utils/unitparser.py
@@ -1,4 +1,6 @@
 import re
+from typing import Optional
+
 from lcwc.agencies.agencyresolver import AgencyResolver
 from lcwc.category import IncidentCategory
 from lcwc.unit import Unit
@@ -8,22 +10,40 @@ class UnitParserException(Exception):
     pass
 
 
+_default_resolver: Optional[AgencyResolver] = None
+
+
+def _get_default_resolver() -> AgencyResolver:
+    """Returns the lazily-built resolver used when a caller supplies none.
+
+    Built on first use rather than at import time so that the roster is not
+    copied for every module that imports this one.
+    """
+    global _default_resolver
+    if _default_resolver is None:
+        _default_resolver = AgencyResolver()
+    return _default_resolver
+
+
 class UnitParser:
     @staticmethod
     def parse_unit(
         unit_str: str,
         category: IncidentCategory,
-        agency_resolver: AgencyResolver = AgencyResolver(),
+        agency_resolver: Optional[AgencyResolver] = None,
     ) -> Unit:
         """Parses the given unit string and returns a Unit object
 
         :param unit_str: The unit string to parse
         :param category: The category for for the unit
-        :param agency_resolver: The agency resolver to use for agency lookups (required for shorthand unit names)
+        :param agency_resolver: The agency resolver to use for agency lookups (required for shorthand unit names). Defaults to a resolver holding the known agencies.
         :return: A Unit object
         :rtype: Unit
         """
 
+        if agency_resolver is None:
+            agency_resolver = _get_default_resolver()
+
         is_shorthand = " " not in unit_str
         if is_shorthand:
             return UnitParser.__parse_short_name(unit_str, category, agency_resolver)
diff --git a/src/lcwc/web/client.py b/src/lcwc/web/client.py
index fc31dfb..8c20634 100644
--- a/src/lcwc/web/client.py
+++ b/src/lcwc/web/client.py
@@ -1,3 +1,5 @@
+from typing import Optional
+
 import aiohttp
 from lcwc import Client
 from lcwc.agencies.agencyresolver import AgencyResolver
@@ -11,8 +13,10 @@ class WebClient(Client):
     URL = "https://www.lcwc911.us/live-incident-list"
     """ The URL of the live incident page """
 
-    def __init__(self, agency_resolver: AgencyResolver = AgencyResolver()) -> None:
-        self.agency_resolver = agency_resolver
+    def __init__(self, agency_resolver: Optional[AgencyResolver] = None) -> None:
+        self.agency_resolver = (
+            agency_resolver if agency_resolver is not None else AgencyResolver()
+        )
         self.parser = WebParser()
 
     @property
diff --git a/src/lcwc/web/parser.py b/src/lcwc/web/parser.py
index defb1a9..251ac88 100644
--- a/src/lcwc/web/parser.py
+++ b/src/lcwc/web/parser.py
@@ -3,7 +3,6 @@
 from bs4 import BeautifulSoup
 import pytz
 from lcwc.agencies.agencyresolver import AgencyResolver
-from lcwc.agencies.exceptions import OutOfCountyException, PendingUnitException
 from lcwc.category import IncidentCategory
 from lcwc.utils.unitparser import UnitParser, UnitParserException
 
@@ -80,10 +79,6 @@ def parse(self, html: str, agency_resolver: AgencyResolver) -> list[WebIncident]
                     try:
                         u = UnitParser.parse_unit(unit_name, category, agency_resolver)
                         units.append(u)
-                    except OutOfCountyException:
-                        self.logger.debug(f"Unit {unit_name} is out of county")
-                    except PendingUnitException:
-                        self.logger.debug(f"Unit {unit_name} is pending")
                     except UnitParserException:
                         self.logger.debug(f"Unable to parse unit {unit_name}")