diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index 601f647..0f2fe08 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -1,113 +1,52 @@
-# For help debugging build failures open an issue on the RStudio community with the 'github-actions' tag.
-# https://community.rstudio.com/new-topic?category=Package%20development&tags=github-actions
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
 on:
   push:
-    branches:
-      - main
-      - master
-      - pre-release
+    branches: [main, master]
   pull_request:
-    branches:
-      - main
-      - master
-      - pre-release
+    branches: [main, master]
 
 name: R-CMD-check
 
+permissions: read-all
+
 jobs:
   R-CMD-check:
-    runs-on: ${{ matrix.os }}
-    name: ${{ matrix.os }} (R ${{ matrix.r }})
+    runs-on: ${{ matrix.config.os }}
+
+    name: ${{ matrix.config.os }} (${{ matrix.config.r }})
 
     strategy:
       fail-fast: false
       matrix:
-        r: ['4.3.3']
-        os: [ubuntu-latest, macOS-latest, windows-latest]
+        config:
+          - {os: macos-latest,   r: 'release'}
+          - {os: windows-latest, r: 'release'}
+          - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
+          - {os: ubuntu-latest,   r: 'release'}
+          - {os: ubuntu-latest,   r: 'oldrel-1'}
 
     env:
-      R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
-      R_REMOTES_UPGRADE: never
-      VDIFFR_RUN_TESTS: true
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
-      _R_CHECK_LENGTH_1_CONDITION_: TRUE #deprecated from R 4.2.0
-      _R_CHECK_MATRIX_DATA_: TRUE # only works from R 4.2.0 onwards
+      R_KEEP_PKG_SOURCE: yes
 
     steps:
       - uses: actions/checkout@v4
 
+      - uses: r-lib/actions/setup-pandoc@v2
+
       - uses: r-lib/actions/setup-r@v2
         with:
-          r-version: ${{ matrix.r }}
-
-      - name: Install system dependencies on macOS
-        if: runner.os == 'macOS'
-        run: |
-          # see https://github.com/orgs/Homebrew/discussions/4612
-          unset HOMEBREW_NO_INSTALL_FROM_API
-          brew update
-          brew install --cask xquartz
-          brew install libarchive
-        shell: bash
-        
-      - name: Install system dependencies on macOS specific to R devel
-        if: runner.os == 'macOS' && matrix.r == 'devel'
-        run: |
-          # ragg                                          requires harfbuzz fribidi
-          # The dependencies of the two R packages below are required for compiling from source on Ubuntu, but macOS seems fine without them
-          # credentials   (dependency of usethis)         requires libgit2
-          # curl          (dependency of usethis)         requires openssl
-          
-          brew install harfbuzz fribidi libgit2 openssl curl
-        shell: bash
+          r-version: ${{ matrix.config.r }}
+          http-user-agent: ${{ matrix.config.http-user-agent }}
+          use-public-rspm: true
 
-      - name: Install system dependencies on linux
-        if: runner.os == 'Linux'
-        run: |
-          # ragg                                          requires libharfbuzz-dev libfribidi-dev 
-          # credentials   (dependency of usethis)         requires libgit2-dev
-          # curl          (dependency of usethis)         requires libcurl4-openssl-dev
-          # libicu   (dependency of igraph or stringi...) requires libicu libicu-dev
-
-          sudo apt install libharfbuzz-dev libfribidi-dev libgit2-dev libcurl4-openssl-dev libicu*
-        shell: bash
-
-      - name: Install dependencies
-        run: |
-          install.packages("remotes")
-          remotes::install_deps(dependencies = TRUE)
-          remotes::install_cran("rcmdcheck")
-        shell: Rscript {0}
-        
-      - name: Check
-        if: runner.os != 'Windows'
-        env:
-          _R_CHECK_CRAN_INCOMING_REMOTE_: false
-        run: |
-          options(crayon.enabled = TRUE)
-          rcmdcheck::rcmdcheck(
-            args        = c("--no-manual", "--as-cran", "--ignore-vignettes"),
-            build_args  = c("--no-build-vignettes"),
-            error_on    = "warning",
-            check_dir   = "check")
-        shell: Rscript {0}"
-
-      - name: Check
-        if: runner.os == 'Windows'
-        env:
-          _R_CHECK_CRAN_INCOMING_REMOTE_: false
-        run: |
-          options(crayon.enabled = TRUE)
-          rcmdcheck::rcmdcheck(
-            args        = c("--no-manual", "--as-cran", "--ignore-vignettes"),
-            build_args  = c("--no-build-vignettes"),
-            error_on    = "warning",
-            check_dir   = "check")
-        shell: Rscript {0}
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: any::rcmdcheck
+          needs: check
 
-      - name: Upload check results
-        if: failure()
-        uses: actions/upload-artifact@main
+      - uses: r-lib/actions/check-r-package@v2
         with:
-          name: ${{ runner.os }}-r${{ matrix.config.r }}-results
-          path: check
+          upload-snapshots: true
+          build_args: 'c("--no-manual","--compact-vignettes=gs+qpdf")'
diff --git a/.github/workflows/R-CMD-tests.yaml b/.github/workflows/R-CMD-tests.yaml
index d2682c1..81c0b8d 100644
--- a/.github/workflows/R-CMD-tests.yaml
+++ b/.github/workflows/R-CMD-tests.yaml
@@ -1,19 +1,15 @@
-# For help debugging build failures open an issue on the RStudio community with the 'github-actions' tag.
-# https://community.rstudio.com/new-topic?category=Package%20development&tags=github-actions
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
 on:
   push:
-    branches:
-      - main
-      - master
-      - pre-release
+    branches: [main, master]
   pull_request:
-    branches:
-      - main
-      - master
-      - pre-release
+    branches: [main, master]
 
 name: R-CMD-tests
 
+permissions: read-all
+
 jobs:
   R-CMD-check:
     runs-on: ${{ matrix.config.os }}
@@ -24,45 +20,31 @@ jobs:
       fail-fast: false
       matrix:
         config:
+          - {os: macos-latest,   r: 'release'}
           - {os: windows-latest, r: 'release'}
-          - {os: macOS-latest,   r: 'release'}
-          - {os: ubuntu-latest,  r: 'release'}
+          - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
+          - {os: ubuntu-latest,   r: 'release'}
+          - {os: ubuntu-latest,   r: 'oldrel-1'}
 
     env:
-      R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
-      RSPM: ${{ matrix.config.rspm }}
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+      R_KEEP_PKG_SOURCE: yes
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
+
+      - uses: r-lib/actions/setup-pandoc@v2
 
       - uses: r-lib/actions/setup-r@v2
         with:
           r-version: ${{ matrix.config.r }}
+          http-user-agent: ${{ matrix.config.http-user-agent }}
+          use-public-rspm: true
 
-      - uses: r-lib/actions/setup-pandoc@v2
-
-      - name: Query dependencies
-        run: |
-          install.packages('remotes')
-          saveRDS(remotes::dev_package_deps(dependencies = TRUE), ".github/depends.Rds", version = 2)
-          writeLines(sprintf("R-%i.%i", getRversion()$major, getRversion()$minor), ".github/R-version")
-        shell: Rscript {0}
-
-      - name: Restore R package cache
-        uses: actions/cache@v2
+      - uses: r-lib/actions/setup-r-dependencies@v2
         with:
-          path: ${{ env.R_LIBS_USER }}
-          key: ${{ runner.os }}-${{ hashFiles('.github/R-version') }}-1-${{ hashFiles('.github/depends.Rds') }}
-          restore-keys: ${{ runner.os }}-${{ hashFiles('.github/R-version') }}-1-
-
-      - name: Install system dependencies
-        if: runner.os == 'Linux'
-        run: |
-          while read -r cmd
-          do
-            eval sudo $cmd
-
+          extra-packages: any::rcmdcheck
+          needs: check
 
       - name: Install and test z-curve (non-Windows)
         env:
diff --git a/.github/workflows/test-coverage.yaml b/.github/workflows/test-coverage.yaml
new file mode 100644
index 0000000..fefc52e
--- /dev/null
+++ b/.github/workflows/test-coverage.yaml
@@ -0,0 +1,61 @@
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+name: test-coverage
+
+permissions: read-all
+
+jobs:
+  test-coverage:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          use-public-rspm: true
+
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: any::covr, any::xml2
+          needs: coverage
+
+      - name: Test coverage
+        run: |
+          cov <- covr::package_coverage(
+            quiet = FALSE,
+            clean = FALSE,
+            install_path = file.path(normalizePath(Sys.getenv("RUNNER_TEMP"), winslash = "/"), "package")
+          )
+          covr::to_cobertura(cov)
+        shell: Rscript {0}
+
+      - uses: codecov/codecov-action@v4
+        with:
+          fail_ci_if_error: ${{ github.event_name != 'pull_request' && true || false }}
+          file: ./cobertura.xml
+          plugin: noop
+          disable_search: true
+          token: ${{ secrets.CODECOV_TOKEN }}
+
+      - name: Show testthat output
+        if: always()
+        run: |
+          ## --------------------------------------------------------------------
+          find '${{ runner.temp }}/package' -name 'testthat.Rout*' -exec cat '{}' \; || true
+        shell: bash
+
+      - name: Upload test results
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-test-failures
+          path: ${{ runner.temp }}/package