UPGRAGE guidelines.
pmacct is developed keeping an eye to backward compatibility: the upgrade to some
newer version should be as smooth as possible from an user standpoint. This is
because, for example, features like SQL table versioning have been introduced
over the time. 
 
However, sometimes the upgrade may require some easy operations aimed to support
the changes done or break old assumptions no longer valid. Such happenings have
been (and will be) very limited through the development process.

TO:	>= 0.14.0rc2
FROM:	<= 0.14.0rc1
TOPIC:	NetFlow v9 sampling
DESC:	Support for sampling in NetFlow v9 and IPFIX is elegant from an architecture
	point of view - but complex if compared to NetFlow v5 and sFlow for example.
	Such increased complexity lacking of proper framing by means of a supportive
	RFC exposes to bizzarre and creative implementations by vendors. 0.14.0rc2
	introduces fixes and workarounds to its sampled NetFlow v9 support in an
	effort to tackle specific but popular platforms among operators - and which
	can result in breaking some backward compatibility in this sense. 0.14.0rc2
	introduces a sampling_map feature, which although not rocket science from a
	concept point of view, it helps supporting sampled NetFlow v9 in heterogeneous
	network hardware environments at the cost of an extra static setting to care
	about; on the other hand it's also true sampling rates are often uniform and
	seldomly redefined in a production network. 
 
TO:	>= 0.8.3 
FROM:	<= 0.8.2 
TOPIC:	Pre-Tagging, Post-Tagging
DESC:	In all previous releases, the 'pre_tag_map' and 'post_tag' directives were
        causing the captured traffic to be automatically tagged while forwarded to
	each active plugin; this behaviour can result in reduced flexibility; the
	0.8.3 release makes the two forementioned directives just to evaluate the
	tag to be assigned to captured traffic; a new 'aggregate' directive keyword
	- tag - causes the traffic to be marked (basing on the previous evaluation).
	So, a configuration like the following:

  	...
	pre_tag_map: /usr/local/pmacct/pre_tag.map
	aggregate[dummy]: src_host,dst_host,src_port,dst_port
	...

	Have to be rewritten the following way in order for the plugin 'dummy' to
	receive the tags:

	...
	pre_tag_map: /usr/local/pmacct/pre_tag.map
	aggregate[dummy]: tag,src_host,dst_host,src_port,dst_port
	... 

TO:     >= 0.10.0
FROM:   <= 0.10.0rc3 
TOPIC:  Configuration directives and command-line options 
DESC:   In all previous releases, commandline options ( ie. -D -c ) were mutually
	exclusive with respect to configuration directives; now, they can cohexist
	and, more specifically, commandline options will override the content of
	the configuration file. This exposes to more interesting usages:

	shell> pmacctd -I <tracefile> -f <cfg>
	to launch pmacctd sharing an unique configuration file while reading data
	from different tcpdump/ethereal tracefiles among multiple runs.

TO:     >= 0.12.0rc1
FROM:   <= 0.11
TOPIC:  agent_id size and SQL table schemas
DESC:   With release 0.12, the agent_id field becomes 4-bytes large (from 2-bytes
	previously). SQL table schemas have been updated accordingly. If running
	a previous release and upgrading, you might incur into the risk that both
	Pre/Post-tagging infrastructures will accept values up to ~4M while the
	underlying SQL table schema is configured with a 2-bytes field. Solution
	is to run an "ALTER TABLE" statement to increase the field size during a
	maintenance window. 

TOPIC:  nfprobe plugin: NetFlow v9 and 32-bit ASNs
DESC:	Release 0.12 introduces support for 32-bit ASNs in pmacct; things do not
	change in NetFlow v5 as if a 32-bit ASN is encountered, it is written as
	AS23456. In NetFlow v9, though, the source and destination AS fields are
	specified as 4 bytes long in the template. Given the template nature of
	NetFlow v9, this shouldn't pose a problem with 3rd party implementations
	but it's better to pay some extra attention while upgrading an existing
	installation.

TO:	>= 0.12.1
FROM	<= 0.12.0
TOPIC:  Data source for ASNs must be explicitely defined
DESC:   data source for 'src_as' and 'dst_as' primitives for nfprobe and sfprobe
        plugins is now expected to be explicitely defined via the [ pmacctd_as |
	uacctd_as ] directive. All other plugins were already working like that.
	In terms of backward compatibility the only case affected is getting ASN
	values out of a Networks File: up to 0.12.0, it was sufficient to define
	a networks_file to implicitely use it.

[EOF]
