diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index bb16d272..ac8117d7 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -20,12 +20,12 @@ certora-test:
     - apt-get update || apt-get update
     - apt-get install -y software-properties-common
     - pip3 install certora-cli-beta==0.4.1
-    - wget https://github.com/ethereum/solidity/releases/download/v0.6.8/solc-static-linux
+    - wget https://github.com/ethereum/solidity/releases/download/v0.6.12/solc-static-linux
     - chmod +x solc-static-linux
     - mv solc-static-linux /usr/bin/solc
     - export PATH=$PATH:/usr/bin/solc/solc-static-linux
   script:
     - certoraRun specs/harness/StableDebtTokenHarness.sol:StableDebtTokenHarness --verify StableDebtTokenHarness:specs/StableDebtToken.spec --settings -assumeUnwindCond --cache StableDebtToken --staging
     - certoraRun specs/harness/UserConfigurationHarness.sol --verify UserConfigurationHarness:specs/UserConfiguration.spec --settings -useBitVectorTheory --staging
-    - certoraRun contracts/tokenization/VariableDebtToken.sol:VariableDebtToken specs/harness/LendingPoolHarnessForVariableDebtToken.sol --link VariableDebtToken:POOL=LendingPoolHarnessForVariableDebtToken --verify VariableDebtToken:specs/VariableDebtToken.spec --settings -assumeUnwindCond,-useNonLinearArithmetic --cache VariableDebtToken --staging
+    - certoraRun contracts/tokenization/VariableDebtToken.sol:VariableDebtToken specs/harness/LendingPoolHarnessForVariableDebtToken.sol --solc_args '--optimize' --link VariableDebtToken:POOL=LendingPoolHarnessForVariableDebtToken --verify VariableDebtToken:specs/VariableDebtToken.spec --settings -assumeUnwindCond,-useNonLinearArithmetic,-b=4 --cache VariableDebtToken --staging