diff --git a/.circleci/install_dependencies.sh b/.circleci/install_dependencies.sh
index 75172376..3071ff2f 100755
--- a/.circleci/install_dependencies.sh
+++ b/.circleci/install_dependencies.sh
@@ -47,11 +47,11 @@ PATH="${PYENV_ROOT}/bin:${PATH}"
 eval "$(pyenv init -)"
 
 if [ "${YCMD_PYTHON_VERSION}" == "2.7" ]; then
-  # We need a recent enough version of Python 2.7 on macOS or an error occurs
-  # when installing the psutil dependency for our tests.
-  PYENV_VERSION="2.7.14"
+  # Prior versions fail to compile with error "ld: library not found for
+  # -lSystemStubs"
+  PYENV_VERSION="2.7.2"
 else
-  PYENV_VERSION="3.4.7"
+  PYENV_VERSION="3.4.0"
 fi
 
 # In order to work with ycmd, python *must* be built as a shared library. The
diff --git a/ci/travis/travis_install.sh b/ci/travis/travis_install.sh
index 3283c3d2..9436c750 100644
--- a/ci/travis/travis_install.sh
+++ b/ci/travis/travis_install.sh
@@ -41,9 +41,11 @@ export PATH="${PYENV_ROOT}/bin:${PATH}"
 eval "$(pyenv init -)"
 
 if [ "${YCM_PYTHON_VERSION}" == "2.7" ]; then
-  PYENV_VERSION="2.7.14"
+  # Tests are failing on Python 2.7.0 with the exception
+  # "TypeError: argument can't be <type 'unicode'>"
+  PYENV_VERSION="2.7.1"
 else
-  PYENV_VERSION="3.4.7"
+  PYENV_VERSION="3.4.0"
 fi
 
 # In order to work with ycmd, python *must* be built as a shared library. This