diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 927961a1f4..ab26b67bd3 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -92,7 +92,7 @@ cxx_binary_tests:
   script:
     - export CONDA_PREFIX="$HOME/conda_root"
     - export PATH="$HOME/conda_root/bin:$PATH"
-    - conda install -c conda-forge toml lld=9.0.1 llvmdev=9.0.1
+    - conda install -c conda-forge toml lld=11.0.1 llvmdev=11.0.1
     - sudo apt-get update
     - sudo apt-get install -yq --no-install-recommends libtinfo-dev zlib1g-dev binutils-dev
     - tar xzf dist/lfortran-*.tar.gz
@@ -229,7 +229,7 @@ build.xsh:
     - export PATH="$HOME/conda_root/bin:$PATH"
     - sudo apt-get update
     - sudo apt-get install -yq --no-install-recommends zlib1g-dev git
-    - conda install -c conda-forge llvmdev=9.0.1 toml pytest jupyter xeus xtl nlohmann_json cppzmq jupyter_kernel_test
+    - conda install -c conda-forge llvmdev=11.0.1 toml pytest jupyter xeus xtl nlohmann_json cppzmq jupyter_kernel_test
     - export LFORTRAN_CMAKE_GENERATOR="Unix Makefiles"
     - export WIN=0
     - export MACOS=0
diff --git a/appveyor.yml b/appveyor.yml
index e680680f4e..58778de440 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -8,7 +8,7 @@ build_script:
 - call conda config --set always_yes yes --set changeps1 no
 - call conda info -a
 - call conda update -q conda
-- call conda install -c conda-forge python=3.7 re2c m2-bison xonsh scikit-build llvmdev=8.0.0 jupyter xeus xtl nlohmann_json cppzmq jupyter_kernel_test pytest
+- call conda install -c conda-forge python=3.7 re2c m2-bison xonsh scikit-build llvmdev=11.0.1 jupyter xeus xtl nlohmann_json cppzmq jupyter_kernel_test pytest
 - set CONDA_PREFIX=C:\\Miniconda37-x64
 - set WIN=1
 - set MACOS=0
diff --git a/ci/azure_install_macos.sh b/ci/azure_install_macos.sh
index 39f84f4240..9625762813 100755
--- a/ci/azure_install_macos.sh
+++ b/ci/azure_install_macos.sh
@@ -5,7 +5,7 @@ set -ex
 conda config --set always_yes yes --set changeps1 no
 conda info -a
 conda update -q conda
-conda install -c conda-forge python=3.7 re2c bison m4 xonsh scikit-build llvmdev=9.0.1 toml cmake=3.17.0 jupyter pytest xeus xtl nlohmann_json cppzmq jupyter_kernel_test
+conda install -c conda-forge python=3.7 re2c bison m4 xonsh scikit-build llvmdev=11.0.1 toml cmake=3.17.0 jupyter pytest xeus xtl nlohmann_json cppzmq jupyter_kernel_test
 export MACOSX_DEPLOYMENT_TARGET="10.9"
 export CONDA_PREFIX=/usr/local/miniconda
 export LFORTRAN_CMAKE_GENERATOR="Unix Makefiles"
diff --git a/doc/src/installation.md b/doc/src/installation.md
index 21d510433c..f708b1d36d 100644
--- a/doc/src/installation.md
+++ b/doc/src/installation.md
@@ -82,7 +82,7 @@ export PATH="$HOME/conda_root/bin:$PATH"
 ```
 Then prepare the environment:
 ```bash
-conda create -n lf -c conda-forge llvmdev=9.0.1 bison=3.4 re2c python cmake make toml
+conda create -n lf -c conda-forge llvmdev=11.0.1 bison=3.4 re2c python cmake make toml
 conda activate lf
 ```
 Clone the LFortran git repository:
@@ -128,6 +128,6 @@ Following are the dependencies necessary for installing this
 repository in development mode,
 
 - [Bison - 3.5.1](https://ftp.gnu.org/gnu/bison/bison-3.5.1.tar.xz)
-- [LLVM - 9.0.1](https://github.com/llvm/llvm-project/releases/download/llvmorg-9.0.1/llvm-9.0.1.src.tar.xz)
+- [LLVM - 11.0.1](https://github.com/llvm/llvm-project/releases/download/llvmorg-11.0.1/llvm-11.0.1.src.tar.xz)
 - [re2c - 2.0.3](https://re2c.org/install/install.html)
-- [binutils - 2.31.90](ftp://sourceware.org/pub/binutils/snapshots/binutils-2.31.90.tar.xz) - Make sure that you should enable the required options related to this dependency to build the dynamic libraries (the ones ending with `.so`).
\ No newline at end of file
+- [binutils - 2.31.90](ftp://sourceware.org/pub/binutils/snapshots/binutils-2.31.90.tar.xz) - Make sure that you should enable the required options related to this dependency to build the dynamic libraries (the ones ending with `.so`).