Could not find function "plot_geo"

Dear Friends,

I was trying to replicate the code that’s in Unfortunately I am running into a wall. I get the following error message:

Error in eval(expr, envir, enclos) : could not find function “plot_geo”

I have installed and called the packages plotly and dplyr. Below is my sessionInfo output. I am running R on windows 10. I am very much grateful for you sharing your knowledge.

Thank you so much.

R version 3.1.2 (2014-10-31)
Platform: x86_64-w64-mingw32/x64 (64-bit)

[1] LC_COLLATE=English_United States.1252 LC_CTYPE=English_United States.1252 LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C LC_TIME=English_United States.1252

attached base packages:
[1] stats graphics grDevices utils datasets methods base

other attached packages:
[1] dplyr_0.4.3 plotly_3.4.13 ggplot2_2.1.0

loaded via a namespace (and not attached):
[1] assertthat_0.1 base64enc_0.1-3 colorspace_1.2-6 DBI_0.3.1 digest_0.6.9 grid_3.1.2 gridExtra_2.0.0
[8] gtable_0.1.2 htmltools_0.3 htmlwidgets_0.5 httr_1.1.0 jsonlite_0.9.19 magrittr_1.5 munsell_0.4.3
[15] parallel_3.1.2 plyr_1.8.3 R6_2.1.2 Rcpp_0.12.3 scales_0.3.0 tidyr_0.4.1 tools_3.1.2
[22] viridis_0.3.2

I figured I have an older version of R and plotly that makes things incompatible. Thank you.