[erlang-questions] upgrading erlang servers

[Richard O'Keefe]

On 10/02/2011, at 6:06 PM, Param Jyothi Reddy wrote:

> Hi guys,
> I am new to erlang and was reading "Programming Erlang" by Joe
> Armstrong and one remark in the book surprised me.
> 
> Pg 173: "And same version of erlang [on all nodes]. If you dont do
> this, you'll get serious and mysterious errors.".

There's one possible reason for this.
When you send terms from processes on one node to processes on another,
they are sent in a binary format.  This format has changed from time to
time, and could certainly be improved further.  See the "minor_version"
option in the documentation for erlang:term_to_binary/2.

Since mnesia/ets data also use this format, it's not something anyone
wants to change _often_.