diff --git a/.github/workflows/egret.yml b/.github/workflows/egret.yml
index 4924b58b..4ed6467a 100644
--- a/.github/workflows/egret.yml
+++ b/.github/workflows/egret.yml
@@ -28,8 +28,8 @@ jobs:
             fail-fast: false
             matrix:
                 os: [ubuntu-20.04]
-                python-version: [3.7, 3.8, 3.9, '3.10']
-                pyomo-version: [6.4.0]
+                python-version: [3.8, 3.9, '3.10', '3.11']
+                pyomo-version: [6.4.3]
                 include:
                     - os: macos-latest
                       python-version: 3.7
@@ -39,10 +39,10 @@ jobs:
                       pyomo-version: 6.4.0
                     - os: ubuntu-20.04
                       python-version: 3.7
-                      pyomo-version: main
+                      pyomo-version: 6.4.0
                     - os: ubuntu-20.04
                       python-version: '3.11'
-                      pyomo-version: 6.4.3
+                      pyomo-version: main
         steps:
           - uses: actions/checkout@v3
           - uses: conda-incubator/setup-miniconda@v2
diff --git a/egret/model_library/transmission/branch.py b/egret/model_library/transmission/branch.py
index d4731e0a..9f06019f 100644
--- a/egret/model_library/transmission/branch.py
+++ b/egret/model_library/transmission/branch.py
@@ -19,16 +19,14 @@
 from egret.data.data_utils import zip_items
 from pyomo.core.util import quicksum
 from pyomo.core.expr.numeric_expr import LinearExpression
+from pyomo.common.dependencies import attempt_import
 from collections import OrderedDict
 from pyomo.contrib.fbbt.fbbt import fbbt
 import warnings
 import logging
 from typing import List, Tuple, AbstractSet
-try:
-    import coramin
-    coramin_available = True
-except ImportError:
-    coramin_available = False
+
+coramin, coramin_available = attempt_import("coramin")
 
 
 logger = logging.getLogger(__name__)
diff --git a/egret/model_library/unit_commitment/uc_utils.py b/egret/model_library/unit_commitment/uc_utils.py
index 1b545ecd..54980a9a 100644
--- a/egret/model_library/unit_commitment/uc_utils.py
+++ b/egret/model_library/unit_commitment/uc_utils.py
@@ -111,7 +111,7 @@ def is_var(v):
     return isinstance(v, Var)
 
 def linear_summation(linear_vars, linear_coefs, constant=0.):
-    return quicksum((c*v for c,v in zip(linear_coefs, linear_vars)), start=constant, linear=True)
+    return quicksum((c*v for c,v in zip(linear_coefs, linear_vars)), start=constant)
 
 def _linear_expression(linear_vars, linear_coefs, constant=0.):
     return LinearExpression(linear_vars=linear_vars, linear_coefs=linear_coefs, constant=constant)