diff --git a/.Rbuildignore b/.Rbuildignore
index c9361f7e..0ce310ee 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -15,3 +15,5 @@ travisbuildchildren.sh
 ^\.github$
 ^depends.Rds$
 ^codecov\.yml$
+^CODE_OF_CONDUCT\.md$
+^CRAN-SUBMISSION$
diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index ff3e797e..d5561cd9 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -1,15 +1,14 @@
-#on: push
+# 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
+    branches: [main, master]
   pull_request:
-    branches:
-      - main
-      - master
+    branches: [main, master]
 
-name: R-CMD-check
+name: R-CMD-check.yaml
+
+permissions: read-all
 
 jobs:
   R-CMD-check:
@@ -21,71 +20,42 @@ jobs:
       fail-fast: false
       matrix:
         config:
-          #- {os: windows-latest, r: 'release', rglusenull: "true"}
-          - {os: macOS-latest, r: 'release', rglusenull: "true"}
-          - {os: ubuntu-20.04, r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest", rglusenull: "true", codecov: "true"}
-          #- {os: ubuntu-20.04, r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
+          - {os: macos-latest,    r: 'release'}
+          - {os: windows-latest,  r: 'release'}
+          - {os: ubuntu-latest, r: 'devel', http-user-agent: 'release'}
+          - {os: ubuntu-latest, r: 'release', codecov: 'true'}
+          - {os: ubuntu-latest, r: 'oldrel-1'}
 
     env:
-      R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
-      RSPM: ${{ matrix.config.rspm }}
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
-      RGL_USE_NULL: ${{ matrix.config.rglusenull }}
+      R_KEEP_PKG_SOURCE: yes
+      RGL_USE_NULL: true
 
     steps:
-      - uses: actions/checkout@v2
+      - 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: Rscript -e "install.packages('remotes')" -e "saveRDS(remotes::dev_package_deps(dependencies = TRUE), 'depends.Rds', version = 2)"
-
-      - name: Cache R packages
-        if: runner.os != 'Windows'
-        uses: actions/cache@v1
+      - uses: r-lib/actions/setup-r-dependencies@v2
         with:
-          path: ${{ env.R_LIBS_USER }}
-          key: ${{ runner.os }}-r-${{ matrix.config.r }}-${{ hashFiles('depends.Rds') }}
-          restore-keys: ${{ runner.os }}-r-${{ matrix.config.r }}-
-
-      - name: Install system dependencies
-        if: runner.os == 'Linux'
-        env:
-          RHUB_PLATFORM: linux-x86_64-ubuntu-gcc
-        run: |
-          Rscript -e "remotes::install_github('r-hub/sysreqs')"
-          sysreqs=$(Rscript -e "cat(sysreqs::sysreq_commands('DESCRIPTION'))")
-          sudo -s eval "$sysreqs"
-
-      - name: Install Covr
-        run: Rscript -e "remotes::install_github('r-lib/covr')"
+          extra-packages: any::rcmdcheck, natverse/natcpp
+          needs: check
 
       - name: Build CMTK
+        if: ${{matrix.config.os != 'windows-latest'}}
         run: sh ./build-cmtk.sh
         env:
+          CC: clang
+          CXX: clang++
           MAKEFLAGS: "-j2"
 
-      - name: Install dependencies
-        run: Rscript -e "library(remotes)" -e "update(readRDS('depends.Rds'))" -e "remotes::install_cran('rcmdcheck')"
-
-      - name: Install manual dependencies
-        run: Rscript -e "remotes::install_github('natverse/natcpp')"
-        
-      - name: Check
-        run: Rscript -e "rcmdcheck::rcmdcheck(args = c('--no-manual', '--as-cran'), error_on = 'warning', check_dir = 'check')"
-
-      - name: Upload check results
-        if: failure()
-        uses: actions/upload-artifact@v2
+      - uses: r-lib/actions/check-r-package@v2
         with:
-          name: ${{ runner.os }}-r${{ matrix.config.r }}-results
-          path: check
-
-      - name: Test coverage
-        if: matrix.config.codecov
-        run: |
-          Rscript -e 'covr::codecov(token = "${{secrets.CODECOV_TOKEN}}")'
+          upload-snapshots: true
+          build_args: 'c("--no-manual","--compact-vignettes=gs+qpdf")'
diff --git a/.github/workflows/test-coverage.yaml b/.github/workflows/test-coverage.yaml
new file mode 100644
index 00000000..0aef2381
--- /dev/null
+++ b/.github/workflows/test-coverage.yaml
@@ -0,0 +1,62 @@
+# 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.yaml
+
+permissions: read-all
+
+jobs:
+  test-coverage:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+      RGL_USE_NULL: true
+
+    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
diff --git a/DESCRIPTION b/DESCRIPTION
index ad6c02bf..ea0fc9c5 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -27,7 +27,7 @@ Depends:
     rgl (>= 0.98.1)
 Imports:
     nabor,
-    igraph (>= 0.7.1),
+    igraph (>= 1.0),
     methods,
     filehash (>= 2.3),
     digest,
diff --git a/NAMESPACE b/NAMESPACE
index fdc7683e..a48a203c 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -114,6 +114,7 @@ S3method(ndigest,neuron)
 S3method(ndigest,neuronlistfh)
 S3method(nvertices,default)
 S3method(nvertices,dotprops)
+S3method(nvertices,igraph)
 S3method(nvertices,neuron)
 S3method(nvertices,neuronlist)
 S3method(nvertices,shapelist3d)
@@ -389,27 +390,26 @@ importFrom(digest,digest)
 importFrom(igraph,"V<-")
 importFrom(igraph,E)
 importFrom(igraph,V)
-importFrom(igraph,add.edges)
+importFrom(igraph,add_edges)
 importFrom(igraph,as.directed)
 importFrom(igraph,as.undirected)
 importFrom(igraph,as_edgelist)
-importFrom(igraph,decompose.graph)
+importFrom(igraph,bfs)
+importFrom(igraph,decompose)
 importFrom(igraph,degree)
 importFrom(igraph,delete.vertices)
+importFrom(igraph,dfs)
 importFrom(igraph,diameter)
 importFrom(igraph,distances)
 importFrom(igraph,get.diameter)
-importFrom(igraph,get.shortest.paths)
-importFrom(igraph,get.vertex.attribute)
-importFrom(igraph,graph.bfs)
-importFrom(igraph,graph.dfs)
-importFrom(igraph,is.connected)
-importFrom(igraph,is.directed)
+importFrom(igraph,is_connected)
+importFrom(igraph,is_directed)
 importFrom(igraph,make_empty_graph)
 importFrom(igraph,neighborhood)
 importFrom(igraph,set_edge_attr)
-importFrom(igraph,shortest.paths)
+importFrom(igraph,shortest_paths)
 importFrom(igraph,vcount)
+importFrom(igraph,vertex_attr)
 importFrom(methods,is)
 importFrom(nabor,knn)
 importFrom(nat.utils,RunCmdForNewerInput)
diff --git a/R/graph-nodes.R b/R/graph-nodes.R
index 8778b3ab..b9d56cfc 100644
--- a/R/graph-nodes.R
+++ b/R/graph-nodes.R
@@ -13,7 +13,7 @@
 #'   available). Set to FALSE when this is not desired.
 #' @param exclude.isolated Do not count isolated vertices as root/end points
 #'   (default)
-#' @importFrom igraph V degree get.vertex.attribute
+#' @importFrom igraph V degree vertex_attr
 #' @export
 #' @seealso \code{\link{rootpoints}}, \code{\link{ngraph}}
 #' @examples
@@ -27,7 +27,7 @@
 graph.nodes<-function(x, type=c('root','end','branch'), original.ids='name',
                       exclude.isolated=TRUE){
   type=match.arg(type)
-  if(type=='root' && !is.directed(x))
+  if(type=='root' && !is_directed(x))
     stop("Cannot establish root points for undirected graph")
   
   # root points are those without incoming edges
@@ -42,7 +42,7 @@ graph.nodes<-function(x, type=c('root','end','branch'), original.ids='name',
   }
   
   if(is.character(original.ids))
-    vertex_names=get.vertex.attribute(x, original.ids, index=vertex_idxs)
+    vertex_names=vertex_attr(x, original.ids, index=vertex_idxs)
   if(!is.character(original.ids) || is.null(vertex_names))
     as.integer(vertex_idxs)
   else
diff --git a/R/neuron.R b/R/neuron.R
index 0caa709e..155f8c0f 100644
--- a/R/neuron.R
+++ b/R/neuron.R
@@ -67,7 +67,7 @@
 #' 
 #' # converting back and forth between neurons and graphs
 #' g=as.ngraph(Cell07PNs[[1]])
-#' gstem=igraph::induced.subgraph(g, 1:10)
+#' gstem=igraph::induced_subgraph(g, 1:10)
 #' # this is fine
 #' plot(gstem)
 #' plot(as.neuron(gstem))
@@ -206,9 +206,9 @@ normalise_swc<-function(x, requiredColumns=c('PointNo','Label','X','Y','Z','W','
 #'   (NumPoints,StartPoint,BranchPoints,EndPoints,nTrees,NumSegs,SegList, 
 #'   [SubTrees]) NB SubTrees will only be present when nTrees>1.
 #' @export
-#' @importFrom igraph V V<- vcount decompose.graph
+#' @importFrom igraph V V<- vcount decompose
 #' @rdname neuron
-#' @seealso \code{\link{graph.dfs}, \link{as.seglist}}
+#' @seealso \code{\link{dfs}, \link{as.seglist}}
 as.neuron.ngraph<-function(x, vertexData=NULL, origin=NULL, Verbose=FALSE, ...){
   # translate origin into raw vertex id if necessary 
   if(length(origin)){
@@ -221,11 +221,11 @@ as.neuron.ngraph<-function(x, vertexData=NULL, origin=NULL, Verbose=FALSE, ...){
   # save original vertex ids
   igraph::V(x)$vid=seq.int(igraph::vcount(x))
   # check if we have multiple subgraphs
-  if(igraph::no.clusters(x)>1){
+  if(igraph::count_components(x)>1){
     if(!length(origin)){
       # no origin specified, will pick the biggest subtree
       # decompose into list of subgraphs
-      gg=igraph::decompose.graph(x)
+      gg=igraph::decompose(x)
       # reorder by descending number of vertices
       gg=gg[order(sapply(gg,igraph::vcount), decreasing=TRUE)]
       subtrees=lapply(gg, as.seglist, Verbose=Verbose)
@@ -233,15 +233,15 @@ as.neuron.ngraph<-function(x, vertexData=NULL, origin=NULL, Verbose=FALSE, ...){
       masterg=gg[[1]]
     } else {
       # origin specified, subtree containing origin will be the master
-      cg=igraph::clusters(x)
+      cg=igraph::components(x)
       master_tree_num=cg$membership[origin]
       # make a master graph with the vertices from subgraph including origin
-      masterg=igraph::induced.subgraph(x, which(cg$membership==master_tree_num))
+      masterg=igraph::induced_subgraph(x, which(cg$membership==master_tree_num))
       # ... and then corresponding seglist
       sl=as.seglist(masterg, origin=origin)
       # now deal with remaining vertices
-      remainderg=igraph::induced.subgraph(x, which(cg$membership!=master_tree_num))
-      gg=igraph::decompose.graph(remainderg)
+      remainderg=igraph::induced_subgraph(x, which(cg$membership!=master_tree_num))
+      gg=igraph::decompose(remainderg)
       # reorder by descending number of vertices
       gg=gg[order(sapply(gg,igraph::vcount), decreasing=TRUE)]
       subtrees=c(list(sl),lapply(gg, as.seglist, Verbose=Verbose))
@@ -262,7 +262,7 @@ as.neuron.ngraph<-function(x, vertexData=NULL, origin=NULL, Verbose=FALSE, ...){
   # sort out the vertex information
   # TODO refactor this into a separate function e.g. normalise.swc since
   # we need to do something similar in as.neuron.dataframe and seglist2swc etc
-  d=data.frame(PointNo=get.vertex.attribute(x,'name'))
+  d=data.frame(PointNo=vertex_attr(x,'name'))
   if(is.null(vertexData)){
     # get vertex information from graph object
     xyz=xyzmatrix(x)
@@ -290,7 +290,7 @@ as.neuron.ngraph<-function(x, vertexData=NULL, origin=NULL, Verbose=FALSE, ...){
   
   d=seglist2swc(x=subtrees,d=d)
   d=normalise_swc(d)
-  n=list(d=d,NumPoints=igraph::vcount(masterg),
+  n=list(d=d,NumPoints=nvertices(masterg),
          StartPoint=StartPoint,
          BranchPoints=branchpoints(masterg, original.ids='vid'),
          EndPoints=endpoints(masterg, original.ids='vid'),
@@ -776,7 +776,7 @@ smooth_segment_spline <- function(xyz, ...) {
 #' # now find the points downstream (distal) of that with respect to the root
 #' ng=as.ngraph(n)
 #' # use a depth first search
-#' distal_points=igraph::graph.dfs(ng, root=n$AxonLHEP, unreachable=FALSE,
+#' distal_points=igraph::dfs(ng, root=n$AxonLHEP, unreachable=FALSE,
 #'   mode='out')$order
 #' distal_tree=subset(n, distal_points)
 #' plot(distal_tree, add=TRUE, col='red', lwd=2)
@@ -945,7 +945,7 @@ simplify_neuron <- function(x, n=1, invert=FALSE, ...) {
       # there will be warnings because most branch points will not be reachable
       # from the selected leaf
       res=suppressWarnings(
-        igraph::get.shortest.paths(ng, from = farthest_leaf, 
+        igraph::shortest_paths(ng, from = farthest_leaf, 
                                    to = bps[bps_available], 
                                    mode = "in", weights = NA))
       pathlengths=sapply(res$vpath, length)
@@ -973,7 +973,7 @@ simplify_neuron <- function(x, n=1, invert=FALSE, ...) {
 }
 
 leafpath <- function(ng, from, to) {
-  res=igraph::get.shortest.paths(ng,from = from,to = to,mode = "out", weights=NA)
+  res=igraph::shortest_paths(ng,from = from,to = to,mode = "out", weights=NA)
   as.integer(res$vpath[[1]])
 }
 
@@ -1169,7 +1169,7 @@ stitch_neurons_mst <- function(x, threshold = Inf, k=10L) {
   mod_graph <- igraph::add_edges(ng,edge_list,"weight"= weights)
   
   #Step 7: Find the minimum spanning tree of the new graph..
-  mst <- igraph::minimum.spanning.tree(mod_graph)
+  mst <- igraph::mst(mod_graph)
   
   #Step 8: Find the new edges added by the mst..
   new_edges <- igraph::difference(igraph::E(mst),igraph::E(masterng))
@@ -1208,7 +1208,7 @@ stitch_neurons_mst <- function(x, threshold = Inf, k=10L) {
     warning("The root node doesn't belong to the largest fragment")
   }
   
-  stitchedng=igraph::delete.vertices(stitchedng, verticestoprune)
+  stitchedng=igraph::delete_vertices(stitchedng, verticestoprune)
   
   #Step 11: Set the root of the stitched graph now..
   stitchedneuron <- as.neuron(stitchedng, origin = master_root)
@@ -1411,7 +1411,7 @@ distal_to <- function(x, node.idx=NULL, node.pointno=NULL, root.idx=NULL,
     g=as.directed.usingroot(gorig, root = root.idx)
   }
   
-  #Step3: For each node id, travese the graph from the given node using depth first search and return the visited
+  #Step3: For each node id, traverse the graph from the given node using depth first search and return the visited
   #nodes..
   l=sapply(node.idx, dfs_traversal, g, simplify = FALSE)
   if(length(node.idx)==1) l[[1]] else l
@@ -1419,7 +1419,8 @@ distal_to <- function(x, node.idx=NULL, node.pointno=NULL, root.idx=NULL,
 
 dfs_traversal <- function(x, g) {
   gdfs=igraph::dfs(g, root = x, unreachable = FALSE)
-  as.integer(gdfs$order)[!is.na(gdfs$order)]
+  # nb igraph 2.0 may change signalling for unreached nodes
+  as.integer(gdfs$order)[!(is.na(gdfs$order) | gdfs$order<1)]
 }
 
 
diff --git a/R/ngraph.R b/R/ngraph.R
index 0839d969..4e856d77 100644
--- a/R/ngraph.R
+++ b/R/ngraph.R
@@ -50,12 +50,12 @@
 #' @param vertex.attributes,graph.attributes List of named attributes to be
 #'   added to the graph. The elements of \code{vertex.attributes} must be
 #'   vectors whose length is compatible with the number of elements in the
-#'   graph. See \code{\link[igraph]{set.vertex.attribute}} for details.
+#'   graph. See \code{\link[igraph]{set_vertex_attr}} for details.
 #' @return an \code{igraph} object with additional class \code{ngraph}, having a
 #'   vertex for each entry in vertexnames, each vertex having a \code{label}
 #'   attribute. All vertices are included whether connected or not.
 #' @family neuron
-#' @seealso \code{\link{igraph}}, \code{\link[igraph]{set.vertex.attribute}},
+#' @seealso \code{\link{igraph}}, \code{\link[igraph]{set_vertex_attr}},
 #'   \code{\link{subset.neuron}} for example of graph-based manipulation of a
 #'   neuron, \code{\link{plot3d.ngraph}}
 #' @export
@@ -72,9 +72,9 @@
 #' # find longest path across graph
 #' d=get.diameter(gw)
 #' # make a new neuron using the longest path
-#' gw_spine=as.neuron(induced.subgraph(gw, d))
+#' gw_spine=as.neuron(induced_subgraph(gw, d))
 #' # make a new neuron containing all nodes except those in longest path
-#' gw_antispine=as.neuron(delete.vertices(gw, d))
+#' gw_antispine=as.neuron(delete_vertices(gw, d))
 #'
 #' # note use of bounding box of original neuron to set plot axes
 #' plot(gw_spine, col='red', boundingbox=boundingbox(n))
@@ -110,10 +110,10 @@ ngraph<-function(el, vertexnames, xyz=NULL, diam=NULL, directed=TRUE,
   }
   if(!is.null(diam)) igraph::V(g)$diam=diam
   for(n in names(vertex.attributes)){
-    g=igraph::set.vertex.attribute(g, name=n,value=vertex.attributes[[n]])
+    g=igraph::set_vertex_attr(g, name=n,value=vertex.attributes[[n]])
   }
   for(n in names(graph.attributes)){
-    g=igraph::set.graph.attribute(g, name=n,value=graph.attributes[[n]])
+    g=igraph::set_graph_attr(g, name=n,value=graph.attributes[[n]])
   }
   class(g)=c("ngraph", class(g))
   g
@@ -159,10 +159,10 @@ as.ngraph.neuron<-function(x, directed=TRUE, method=c('swc','seglist'), ...){
 #' @export
 as.ngraph.igraph<-function(x, directed=TRUE, root, mode=c('out','in'), ...){
   if(inherits(x,'ngraph'))
-    if(igraph::is.directed(x)==directed) return(x)
+    if(igraph::is_directed(x)==directed) return(x)
   
-  if(igraph::is.directed(x) && !directed) x=as.undirected(x, ...)
-  else if(!igraph::is.directed(x) && directed) x=as.directed.usingroot(x, root, mode=mode, ...)
+  if(igraph::is_directed(x) && !directed) x=as.undirected(x, ...)
+  else if(!igraph::is_directed(x) && directed) x=as.directed.usingroot(x, root, mode=mode, ...)
   
   if(!inherits(x,'ngraph')){
     class(x)=c("ngraph",class(x))
@@ -173,11 +173,11 @@ as.ngraph.igraph<-function(x, directed=TRUE, root, mode=c('out','in'), ...){
 as.directed.usingroot<-function(g, root, mode=c('out','in')){
   mode=match.arg(mode)
   # make a directed graph _keeping any attributes_
-  if(!igraph::is.directed(g))
+  if(!igraph::is_directed(g))
     dg=igraph::as.directed(g, mode='arbitrary')
   else dg=g
-  dfs=igraph::graph.dfs(dg, root, unreachable=FALSE, dist=TRUE, mode='all')
-  el=igraph::get.edgelist(dg)
+  dfs=igraph::dfs(dg, root, unreachable=FALSE, dist=TRUE, mode='all')
+  el=igraph::as_edgelist(dg)
   
   connected_vertices=which(is.finite(dfs$order))
   edges_to_check=which(el[,1]%in%connected_vertices)
@@ -193,8 +193,8 @@ as.directed.usingroot<-function(g, root, mode=c('out','in')){
   if(any(same_dist)) warning(sum(same_dist)," edges connect vertices that are the same distance from the root => cycles.")
   edges_to_flip <- edges_to_check[if(mode=='out') parent_further else parent_closer]
   
-  dg=igraph::delete.edges(dg,edges_to_flip)
-  dg=igraph::add.edges(dg,t(el[edges_to_flip,2:1]))
+  dg=igraph::delete_edges(dg,edges_to_flip)
+  dg=igraph::add_edges(dg,t(el[edges_to_flip,2:1]))
   dg
 }
 
@@ -225,7 +225,7 @@ as.directed.usingroot<-function(g, root, mode=c('out','in')){
 #'
 #'   }
 #' @seealso \code{\link[igraph]{diameter}},
-#'   \code{\link[igraph]{shortest.paths}}, \code{\link{prune_strahler}} for
+#'   \code{\link[igraph]{distances}}, \code{\link{prune_strahler}} for
 #'   removing lower order branches from a neuron, \code{\link{prune}} for
 #'   removing parts of a neuron by spatial criteria.
 #' @export
@@ -247,7 +247,7 @@ as.directed.usingroot<-function(g, root, mode=c('out','in')){
 #' plot3d(antispine, lwd=4, col='red')
 #' }
 #'
-#' @importFrom igraph shortest.paths get.shortest.paths diameter get.diameter
+#' @importFrom igraph distances shortest_paths diameter get.diameter
 #'   delete.vertices
 #' @family neuron
 spine <- function(n, UseStartPoint=FALSE, SpatialWeights=TRUE, invert=FALSE,
@@ -261,7 +261,7 @@ spine <- function(n, UseStartPoint=FALSE, SpatialWeights=TRUE, invert=FALSE,
   start <- if(UseStartPoint) n$StartPoint else n$EndPoints
   # Find distances for longest shortest paths from given start point(s) to 
   # all end points
-  lps=shortest.paths(graph = ng, start, to = n$EndPoints, mode = 'all')
+  lps=distances(graph = ng, start, to = n$EndPoints, mode = 'all')
   if(rval=='length') return(max(lps))
   if(!UseStartPoint && length(start)>1 && length(n$EndPoints)>1) {
     # we have a square distance matrix which is symmetric across
@@ -273,7 +273,7 @@ spine <- function(n, UseStartPoint=FALSE, SpatialWeights=TRUE, invert=FALSE,
   wmi=arrayInd(which.max(lps), dim(lps))
   from=start[wmi[1]]
   to=n$EndPoints[wmi[2]]
-  longestpath=get.shortest.paths(ng, from = from, to = to, mode = 'all')$vpath[[1]]
+  longestpath=shortest_paths(ng, from = from, to = to, mode = 'all')$vpath[[1]]
   
   if(rval=='ids') {
     if(invert) {
@@ -308,7 +308,7 @@ spine <- function(n, UseStartPoint=FALSE, SpatialWeights=TRUE, invert=FALSE,
 #' @return \code{igraph} object containing only nodes of neuron keeping original
 #'   labels (\code{x$d$PointNo} => \code{V(g)$label}) and vertex indices 
 #'   (\code{1:nrow(x$d)} => \code{V(g)$vid)}.
-#' @importFrom igraph make_empty_graph add.edges E
+#' @importFrom igraph make_empty_graph add_edges E
 #' @export
 #' @examples 
 #' sg=segmentgraph(Cell07PNs[[1]])
@@ -344,9 +344,9 @@ segmentgraph<-function(x, weights=TRUE, segids=FALSE, exclude.isolated=FALSE,
   }
   if(weights){
     weights=seglengths(x, all=TRUE)
-    g=add.edges(g, elred, weight=weights, segid=segids)
+    g=add_edges(g, elred, weight=weights, segid=segids)
   } else {
-    g=add.edges(g, elred, segid=segids)
+    g=add_edges(g, elred, segid=segids)
   }
   
   if(include.xyz){
@@ -357,7 +357,7 @@ segmentgraph<-function(x, weights=TRUE, segids=FALSE, exclude.isolated=FALSE,
   if(exclude.isolated){
     # remove any points with no neighbours
     isolated_vertices=igraph::V(g)[igraph::degree(g)==0]
-    g=igraph::delete.vertices(graph=g,isolated_vertices)
+    g=igraph::delete_vertices(graph=g,isolated_vertices)
   }
   g
 }
@@ -381,7 +381,7 @@ segmentgraph<-function(x, weights=TRUE, segids=FALSE, exclude.isolated=FALSE,
 #' @seealso \code{\link{prune_strahler}}, a \code{\link{segmentgraph}} (a form
 #'   of \code{\link{ngraph}}) representation is used to calculate the Strahler 
 #'   order.
-#' @importFrom igraph graph.bfs neighborhood V
+#' @importFrom igraph bfs neighborhood V
 #' @return A list containing \itemize{
 #'   
 #'   \item points Vector of integer Strahler orders for each point in the neuron
@@ -400,7 +400,7 @@ strahler_order<-function(x){
     return(list(points=rep(1L, nrow(x$d)),
                 segments=rep(1L, length(x$SegList))))
   
-  b=graph.bfs(s, root=roots, mode = 'out', unreachable=F, father=T)
+  b=bfs(s, root=roots, mode = 'out', unreachable=F, father=T)
   
   # find neighbours for each node
   n=neighborhood(s, 1, mode='out')
@@ -533,15 +533,17 @@ prune_strahler<-function(x, orderstoprune=1:2, ...) {
 prune_vertices<-function(x, verticestoprune, invert=FALSE, ...) {
   g=as.ngraph(x)
   
-  # because igraph.vs sequences are atttached to a specific graph
+  # because igraph.vs sequences are attached to a specific graph
   if(inherits(verticestoprune, "igraph.vs")) 
     verticestoprune=as.integer(verticestoprune)
   if(invert) {
-    nvertices=nrow(xyzmatrix(x))
+    nvertices=igraph::vcount(g)
     verticestoprune=setdiff(seq_len(nvertices), verticestoprune)
+  } else {
+    verticestoprune=setdiff(verticestoprune, 0)
   }
-  dg=igraph::delete.vertices(g, verticestoprune)
-  # delete.vertices will return an igraph
+  dg=igraph::delete_vertices(g, verticestoprune)
+  # delete_vertices will return an igraph
   as.neuron(as.ngraph(dg), ...)
 }
 
@@ -583,10 +585,10 @@ prune_edges_ng <- function(g, edges, invert=FALSE) {
   
   if(invert) edges=setdiff(igraph::E(g), edges)
   
-  dg=igraph::delete.edges(g, edges = edges)
+  dg=igraph::delete_edges(g, edges = edges)
   
   # remove unreferenced vertices
-  dg=igraph::delete.vertices(dg, which(igraph::degree(dg, mode='all')==0))
+  dg=igraph::delete_vertices(dg, which(igraph::degree(dg, mode='all')==0))
 }
 
 # Construct EdgeList matrix with start and end points from SegList
diff --git a/R/seglist.R b/R/seglist.R
index c1092855..a07bb33a 100644
--- a/R/seglist.R
+++ b/R/seglist.R
@@ -92,7 +92,7 @@ as.seglist.default<-function(x, ...) stop("Not yet implemented!")
 #' @return a \code{list} with one entry for each unbranched segment.
 #' @seealso \code{\link{ngraph},\link{igraph}}
 #' @export
-#' @importFrom igraph is.directed is.connected graph.dfs degree
+#' @importFrom igraph is_directed is_connected dfs degree
 #' @rdname seglist
 as.seglist.igraph<-function(x, origin=NULL, Verbose=FALSE, ...){
   # Handle degenerate cases
@@ -100,8 +100,8 @@ as.seglist.igraph<-function(x, origin=NULL, Verbose=FALSE, ...){
     if(Verbose) warning("Empty graph! Seglist not defined")
     return(NULL)
   }
-  if(!is.connected(x)) stop("Graph is not fully connected!")
-  if(is.directed(x) && !igraph::is.dag(x)){
+  if(!is_connected(x)) stop("Graph is not fully connected!")
+  if(is_directed(x) && !igraph::is_dag(x)){
     stop("Graph has cycles!")
   }
   
@@ -123,7 +123,7 @@ as.seglist.igraph<-function(x, origin=NULL, Verbose=FALSE, ...){
   # Handle Origin
   if(is.null(origin)){
     # no explicit origin specified, use raw vertex id of graph root
-    if(is.directed(x))
+    if(is_directed(x))
       origin=rootpoints(x, original.ids=FALSE)
   } else {
     # we've been given an origin but it may not be a raw vertex id for this
@@ -140,7 +140,7 @@ as.seglist.igraph<-function(x, origin=NULL, Verbose=FALSE, ...){
   }
   
   # Now do a depth first search to ensure that ordering is correct
-  dfs=graph.dfs(x, root=origin, father=TRUE, mode='all')
+  dfs=dfs(x, root=origin, father=TRUE, mode='all')
   # cache orders for speed: dfs$order[i] is slooooow in igraph>=1.0
   orders=as.integer(dfs$order)
   ncount=degree(x)
diff --git a/R/xform.R b/R/xform.R
index 4a766445..e4b14a99 100644
--- a/R/xform.R
+++ b/R/xform.R
@@ -230,6 +230,13 @@ xform.neuronlist<-function(x, reg, subset=NULL, ..., OmitFailures=NA,
 }
 
 
+#' @rdname nvertices
+#' @export
+nvertices.igraph <- function(x, ...) {
+  # as of igraph 2.0 this is numeric
+  as.integer(igraph::vcount(x))
+}
+
 #' Mirror 3D object about a given axis, optionally using a warping registration
 #' 
 #' @description mirroring with a warping registration can be used to account 
diff --git a/R/xyzmatrix.R b/R/xyzmatrix.R
index 86b52308..a600c7d2 100644
--- a/R/xyzmatrix.R
+++ b/R/xyzmatrix.R
@@ -177,7 +177,7 @@ xyzmatrix.hxsurf<-function(x, ...) {
 #' @rdname xyzmatrix
 #' @export
 xyzmatrix.igraph<-function(x, ...){
-  xyz=sapply(c("X","Y","Z"), function(c) igraph::get.vertex.attribute(x, c))
+  xyz=sapply(c("X","Y","Z"), function(c) igraph::vertex_attr(x, c))
   if(is.list(xyz) && all(sapply(xyz, is.null)))
     xyz = NULL
   xyz
@@ -341,7 +341,7 @@ xyzmatrix2list <- function(x) {
 `xyzmatrix<-.igraph`<-function(x, value){
   colnames(value)=c("X","Y","Z")
   for(col in colnames(value)){
-    x=igraph::set.vertex.attribute(x, col, value=value[,col])
+    x=igraph::set_vertex_attr(x, col, value=value[,col])
   }
   x
 }
diff --git a/README.md b/README.md
index e6d403b4..7a491764 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@
 [![DOI](https://img.shields.io/badge/doi-10.5281%2Fzenodo.10171-blue.svg)](http://dx.doi.org/10.5281/zenodo.10171) 
 [![Release Version](https://img.shields.io/github/release/natverse/nat.svg)](https://github.com/natverse/nat/releases/latest) 
 [![CRAN_Status_Badge](http://www.r-pkg.org/badges/version/nat)](https://cran.r-project.org/package=nat) 
-[![Build status](https://github.com/natverse/nat/workflows/R-CMD-check/badge.svg)](https://github.com/natverse/nat/actions)
+[![R-CMD-check](https://github.com/natverse/nat/actions/workflows/R-CMD-check.yaml/badge.svg)](https://github.com/natverse/nat/actions/workflows/R-CMD-check.yaml)
 [![Coverage Status](https://codecov.io/gh/natverse/nat/branch/master/graph/badge.svg)](https://app.codecov.io/gh/natverse/nat)
 [![Docs](https://img.shields.io/badge/docs-100%25-brightgreen.svg)](https://natverse.org//nat/reference/)
 [![Downloads](http://cranlogs.r-pkg.org/badges/nat?color=brightgreen)](https://www.r-pkg.org:443/pkg/nat)
diff --git a/build-cmtk.sh b/build-cmtk.sh
index 34cdb139..2e1e158c 100755
--- a/build-cmtk.sh
+++ b/build-cmtk.sh
@@ -3,8 +3,9 @@ set -e
 # check to see if cmtk install folder is empty
 if [ ! -d "$HOME/usr/local/bin" ]; then
   mkdir -p $HOME/src && cd $HOME/src
-  git clone --depth 50 https://github.com/jefferis/cmtk
-  cd cmtk/core && mkdir build && cd build && cmake .. && make DESTDIR=$HOME/ all install
+  git clone --depth 10 --branch natdev https://github.com/jefferis/cmtk
+  cd cmtk && git checkout natdev
+  cd core && mkdir build && cd build && cmake .. && make DESTDIR=$HOME/ all install
 else
   echo 'Using cached $HOME/usr/local directory.';
-fi
\ No newline at end of file
+fi
diff --git a/man/neuron.Rd b/man/neuron.Rd
index 4a13771f..7b6af9b9 100644
--- a/man/neuron.Rd
+++ b/man/neuron.Rd
@@ -160,7 +160,7 @@ hist(igraph::distances(ngw))
 
 # converting back and forth between neurons and graphs
 g=as.ngraph(Cell07PNs[[1]])
-gstem=igraph::induced.subgraph(g, 1:10)
+gstem=igraph::induced_subgraph(g, 1:10)
 # this is fine
 plot(gstem)
 plot(as.neuron(gstem))
@@ -178,7 +178,7 @@ plot(as.neuron(gstem2))
 \seealso{
 \code{\link{neuronlist}}
 
-\code{\link{graph.dfs}, \link{as.seglist}}
+\code{\link{dfs}, \link{as.seglist}}
 
 Other neuron: 
 \code{\link{ngraph}()},
diff --git a/man/ngraph.Rd b/man/ngraph.Rd
index 10baa693..be9772c4 100644
--- a/man/ngraph.Rd
+++ b/man/ngraph.Rd
@@ -45,7 +45,7 @@ when 4th column is assumed to be diameter)}
 \item{vertex.attributes, graph.attributes}{List of named attributes to be
 added to the graph. The elements of \code{vertex.attributes} must be
 vectors whose length is compatible with the number of elements in the
-graph. See \code{\link[igraph]{set.vertex.attribute}} for details.}
+graph. See \code{\link[igraph]{set_vertex_attr}} for details.}
 
 \item{x}{Object to convert (see method descriptions)}
 
@@ -126,16 +126,16 @@ gw=as.ngraph(n, weights=TRUE)
 # find longest path across graph
 d=get.diameter(gw)
 # make a new neuron using the longest path
-gw_spine=as.neuron(induced.subgraph(gw, d))
+gw_spine=as.neuron(induced_subgraph(gw, d))
 # make a new neuron containing all nodes except those in longest path
-gw_antispine=as.neuron(delete.vertices(gw, d))
+gw_antispine=as.neuron(delete_vertices(gw, d))
 
 # note use of bounding box of original neuron to set plot axes
 plot(gw_spine, col='red', boundingbox=boundingbox(n))
 plot(gw_antispine, col='blue', add=TRUE)
 }
 \seealso{
-\code{\link{igraph}}, \code{\link[igraph]{set.vertex.attribute}},
+\code{\link{igraph}}, \code{\link[igraph]{set_vertex_attr}},
   \code{\link{subset.neuron}} for example of graph-based manipulation of a
   neuron, \code{\link{plot3d.ngraph}}
 
diff --git a/man/nvertices.Rd b/man/nvertices.Rd
index 8de405a7..136faf04 100644
--- a/man/nvertices.Rd
+++ b/man/nvertices.Rd
@@ -1,12 +1,15 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/xyzmatrix.R
-\name{nvertices}
+% Please edit documentation in R/xform.R, R/xyzmatrix.R
+\name{nvertices.igraph}
+\alias{nvertices.igraph}
 \alias{nvertices}
 \alias{nvertices.default}
 \alias{nvertices.neuronlist}
 \alias{nvertices.shapelist3d}
 \title{Find the number of vertices in an object (or each element of a neuronlist)}
 \usage{
+\method{nvertices}{igraph}(x, ...)
+
 nvertices(x, ...)
 
 \method{nvertices}{default}(x, ...)
diff --git a/man/spine.Rd b/man/spine.Rd
index bb975bc9..b461bb59 100644
--- a/man/spine.Rd
+++ b/man/spine.Rd
@@ -69,7 +69,7 @@ plot3d(antispine, lwd=4, col='red')
 }
 \seealso{
 \code{\link[igraph]{diameter}},
-  \code{\link[igraph]{shortest.paths}}, \code{\link{prune_strahler}} for
+  \code{\link[igraph]{distances}}, \code{\link{prune_strahler}} for
   removing lower order branches from a neuron, \code{\link{prune}} for
   removing parts of a neuron by spatial criteria.
 
diff --git a/man/subset.neuron.Rd b/man/subset.neuron.Rd
index 15a498a5..3aac2c2e 100644
--- a/man/subset.neuron.Rd
+++ b/man/subset.neuron.Rd
@@ -69,7 +69,7 @@ points(t(xyzmatrix(n)[n$AxonLHEP, 1:2]), pch=19, cex=2.5)
 # now find the points downstream (distal) of that with respect to the root
 ng=as.ngraph(n)
 # use a depth first search
-distal_points=igraph::graph.dfs(ng, root=n$AxonLHEP, unreachable=FALSE,
+distal_points=igraph::dfs(ng, root=n$AxonLHEP, unreachable=FALSE,
   mode='out')$order
 distal_tree=subset(n, distal_points)
 plot(distal_tree, add=TRUE, col='red', lwd=2)
diff --git a/tests/testthat/test-cmtk.R b/tests/testthat/test-cmtk.R
index 922600d3..8dca925a 100644
--- a/tests/testthat/test-cmtk.R
+++ b/tests/testthat/test-cmtk.R
@@ -6,6 +6,9 @@ test_that("cmtk.bindir works when CMTK is in the path",{
   # We're going to set up some fake directories to look like
   # different kinds of CMTK installation
   
+  # some spurious failures on windows actions
+  skip_on_os(os = 'windows')
+  
   td <- tempfile(pattern = 'nat-cmtk-test')
   makeexecfile <- function(p) {
     fullp <- file.path(td, p)
diff --git a/tests/testthat/test-neuron.R b/tests/testthat/test-neuron.R
index 519173ee..e42d6f21 100644
--- a/tests/testthat/test-neuron.R
+++ b/tests/testthat/test-neuron.R
@@ -273,7 +273,7 @@ test_that("we can subset a neuron", {
 
 test_that("we can subset a neuron with a vertex sequence", {
   n = Cell07PNs[[1]]
-  n_graph_dfs = igraph::graph.dfs(as.ngraph(n), root = 48, mode = "out", unreachable = FALSE)
+  n_graph_dfs = igraph::dfs(as.ngraph(n), root = 48, mode = "out", unreachable = FALSE)
   expect_is(n_subset <- subset(n, n_graph_dfs$order, invert = F), 'neuron')
   expect_is(n_subset <- subset(n, n_graph_dfs$order, invert = T), 'neuron')
 })
diff --git a/tests/testthat/test-ngraph.R b/tests/testthat/test-ngraph.R
index 293c1ac7..1806e585 100644
--- a/tests/testthat/test-ngraph.R
+++ b/tests/testthat/test-ngraph.R
@@ -1,5 +1,5 @@
 context("ngraph class")
-library(igraph, warn.conflicts = FALSE)
+suppressPackageStartupMessages(library(igraph, warn.conflicts = FALSE))
 
 # make a very simple neuron
 # 1 2 3b 4 5
@@ -13,7 +13,7 @@ test_that("as.ngraph can convert swc data into an ngraph object",{
   expect_is(g1,'ngraph')
   
   # check we keep ngraph class when modifying ngraph
-  expect_is(set.graph.attribute(g1,'origin',1),'ngraph')
+  expect_is(set_graph_attr(g1,'origin',1),'ngraph')
   
   # same neuron with PointNo 2 greater
   testd2=data.frame(PointNo=3:8,Label=2,
@@ -144,13 +144,13 @@ test_that("setting of graph attributes",{
   gatts=list(name='testneuron',nclass="PN")
   expect_is(testg <- as.ngraph(testd, graph.attributes = gatts, 
                                vertex.attributes=list(X=testd$X)), 'ngraph')
-  expect_equal(get.graph.attribute(testg, name = 'nclass'), gatts$nclass)
-  expect_equal(get.graph.attribute(testg, name = 'name'), gatts$name)
+  expect_equal(graph_attr(testg, name = 'nclass'), gatts$nclass)
+  expect_equal(graph_attr(testg, name = 'name'), gatts$name)
   # null attributes
-  expect_equal(get.graph.attribute(testg, name = 'rhubarb'), gatts$rhubarb)
+  expect_equal(graph_attr(testg, name = 'rhubarb'), gatts$rhubarb)
   
   # vertex attributes
-  expect_equal(get.vertex.attribute(testg, name = 'X'), testd$X)
+  expect_equal(vertex_attr(testg, name = 'X'), testd$X)
   if(igraph::igraph_version()>=numeric_version("1.3.5.9098"))
     expect_error(testg <- as.ngraph(testd, graph.attributes = gatts, 
                                     vertex.attributes=list(X=testd$X[-1])))