Strategy 'multiprocess' is deprecated in future (>= 1.20.0)

[doncqueurs]

When I run the example "shiny.worker demo" I get the following error message:

Warning: Strategy 'multiprocess' is deprecated in future (>= 1.20.0). Instead, explicitly specify either 'multisession' or 'multicore'. In the current R session, 'multiprocess' equals 'multisession'.

When I replace (in worker.R):

#' Initialize the worker's registry
initialize = function() {
   plan(multiprocess)
},

with:

initialize = function() {
   plan(multisession)
},

Things work fine.