diff --git a/mythril/version.py b/mythril/version.py
index 209f9662..edb5e509 100644
--- a/mythril/version.py
+++ b/mythril/version.py
@@ -1,3 +1,3 @@
 # This file is suitable for sourcing inside POSIX shell, e.g. bash as
 # well as for importing into Python
-VERSION = "v0.18.13"  # NOQA
+VERSION = "v0.19.1"  # NOQA
diff --git a/requirements.txt b/requirements.txt
index 3691a704..252538c5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -24,5 +24,5 @@ pytest_mock
 requests
 rlp>=1.0.1
 transaction>=2.2.1
-z3-solver>=4.8
+z3-solver==4.5.1.0.post2
 pysha3
diff --git a/setup.py b/setup.py
index c52d2153..4a33a0dc 100755
--- a/setup.py
+++ b/setup.py
@@ -75,7 +75,7 @@ setup(
     install_requires=[
         "coloredlogs>=10.0",
         "ethereum>=2.3.2",
-        "z3-solver>=4.8",
+        "z3-solver==4.5.1.0.post2",
         "requests",
         "py-solc",
         "plyvel",