diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 1d8f4d142e693fa6135487d8bd297ccd52fa9d3e..21b971fb3eabeb862465c3a6359ee45ac5f1f988 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -2,7 +2,7 @@ default:
   tags: [docker]
   image: r-base:latest
   before_script:
-    - Rscript -e 'install.packages(c("remotes", "dplyr"))'
+    - Rscript -e 'install.packages(c("remotes", "dplyr", "knitr"))'
     - Rscript -e 'remotes::install_gitlab("HYCAR-Hydro/airgr@sd", host = "gitlab.irstea.fr")'
     - R CMD build ../griwrm