diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 9156514..1208424 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -38,7 +38,6 @@ jobs:
         with:
           r-version: ${{ matrix.config.r }}
           http-user-agent: ${{ matrix.config.http-user-agent }}
-          use-public-rspm: true
 
       - uses: r-lib/actions/setup-r-dependencies@v2
         with:
diff --git a/.github/workflows/pkgdown.yaml b/.github/workflows/pkgdown.yaml
index d7322a3..3c0e4e5 100644
--- a/.github/workflows/pkgdown.yaml
+++ b/.github/workflows/pkgdown.yaml
@@ -28,8 +28,6 @@ jobs:
       - uses: r-lib/actions/setup-pandoc@v2
 
       - uses: r-lib/actions/setup-r@v2
-        with:
-          use-public-rspm: true
 
       - uses: r-lib/actions/setup-r-dependencies@v2
         with:
@@ -42,7 +40,7 @@ jobs:
 
       - name: Deploy to GitHub pages 🚀
         if: github.event_name != 'pull_request'
-        uses: JamesIves/github-pages-deploy-action@v4.5.0
+        uses: JamesIves/github-pages-deploy-action@d92aa235d04922e8f08b40ce78cc5442fcfbfa2f # v4.8.0
         with:
           clean: false
           branch: gh-pages
diff --git a/DESCRIPTION b/DESCRIPTION
index 163dfd4..f1e1895 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -9,8 +9,6 @@ Authors@R:
 Description: Infer causation from observational data through pattern causality analysis (PC), with original algorithm for time series data from Stavroglou et al. (2020) <doi:10.1073/pnas.1918269117>, as well as methodological extensions for spatial cross-sectional data introduced by Zhang & Wang (2025) <doi:10.1080/13658816.2025.2581207>, together with a systematic description proposed in Lyu et al. (2026) <doi:10.1016/j.compenvurbsys.2026.102435>.
 License: GPL-3
 Encoding: UTF-8
-Roxygen: list(markdown = TRUE)
-RoxygenNote: 7.3.3
 URL: https://stscl.github.io/pc/, https://github.com/stscl/pc
 BugReports: https://github.com/stscl/pc/issues
 Depends: 
@@ -35,3 +33,5 @@ Suggests:
     knitr,
     rmarkdown
 VignetteBuilder: knitr
+Config/roxygen2/markdown: TRUE
+Config/roxygen2/version: 8.0.0
diff --git a/R/zzz.R b/R/zzz.R
index ab6b38e..f45e1d2 100644
--- a/R/zzz.R
+++ b/R/zzz.R
@@ -1,4 +1,3 @@
 .onLoad = \(...) {
-  loadNamespace("sf")
-  loadNamespace("terra")
+  requireNamespace("Rcpp", quietly = TRUE)
 }