% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/versions.R
\name{graph_version}
\alias{graph_version}
\title{igraph data structure versions}
\usage{
graph_version(graph)
}
\arguments{
\item{graph}{The input graph. If it is missing, then
the version number of the current data format is returned.}
}
\value{
An integer scalar.
}
\description{
igraph's internal data representation changes sometimes between
versions. This means that it is not always possible to use igraph objects
that were created (and possibly saved to a file) with an older
igraph version.
}
\details{
\code{graph_version()} queries the current data format,
or the data format of a possibly older igraph graph.

\code{\link[=upgrade_graph]{upgrade_graph()}} can convert an older data format
to the current one.
}
\seealso{
upgrade_graph to convert the data format of a graph.

Other versions: 
\code{\link{upgrade_graph}()}
}
\concept{versions}
