06/24/2010 1.9.1

The old genpois function is now removed.

05/02/2010 1.9.0

Many old (and now undocumented) aliasas are now officially 
deprecated and will be removed before long, including the 
following:

noecho   (use "set echo off")
seed X   (use "set seed X")
end if   (use "endif")
corc     (use "ar1")
hilu     (use "ar1 ... --hilu")
pwe      (use "ar1 ... --pwe")
hccm     (use "ols ... --jackknife")
lmtest   (use "modtest")
testuhat (use "modtest")

The following parameters to the "set" command are now declared
obsolete and will be removed before long: bkbp_k, bkbp_limits,
hp_lambda. Use the optional arguments to the functions 
bkfilt and hpfilt instead.

Gretl now requires gnuplot version 4.2.0 or higher for
graphing.  Since version 4.2 was released in March 2007,
hopefully this should not be too onerous.

The "criteria" command has been removed.  A small function
package is available on the gretl server that replaces this
command.

The commands "graph" and "plot" have been consolidated as
options to the new command "textplot"; but the old commands
are retained as aliases for the present.

The function genpois() is now deprecated.  Please use
randgen() with a first argument of 'P' instead.

The --continue option for the commands arma, garch, mle
nls and gmm (which allowed continuation of script execution
in face of an error) is now deprecated in favor of the
new "catch" prefix, as in "catch arma 2 2 ; y".  For the
present the --continue option remains an acceptable alias
for the use of "catch", but this will be removed at some
point.

The internal variable "obs" used to get the year in the
case of annual time series data, but a 1-based index in all
other cases.  This has now been made consistent: it always
gives the 1-based index.  Any scripts that rely on the old
behavior with annual data can be fixed quite easily --
substitute, e.g., "obsnum(1970)" for plain "1970" when you
wish to compare a year against the obs series.  For example, 
to create a dummy variable with value 1 in 1970 only:

  series d70 = (obs=obsnum(1970))? 1 : 0

01/24/2010 version 1.8.7

The accessor $vcv is no longer available for VARs.  The
full covariance matrix can be retrieved as 

  $sigma ** $xtxinv 

where "**" is the Kronecker product operator and $xtxinv
is a newly defined accessor for X'X^{-1}.

With the new (and faster) Ziggurat implementation for the
normal RNG, gretl 1.8.7 will not produce the same sequence
of normal samples for a given random seed as gretl <= 1.8.6.
However, you can force backward compatibility by doing
"set normal_rand box-muller".

11/25/2009 version 1.8.6

ARIMAX models (i.e. ARIMA models with non-zero order of 
integration and including exogenous regressors): we now
follow the practice of most ARIMA software, and apply the
differencing operator to both the dependent variable
and the exogenous regressors.  Previously gretl left the
regressors in level form; you can reinstate that
behavior via a new "arima" option, --y-diff-only.

10/10/2009 version 1.8.5

The --long option to the "print" command has been removed,
along with the longdigits variable in the "set" command.
These were long ago rendered redundant by the "printf"
command.

8/28/2009 version 1.8.4

Gretl uses "to" as a syntactic element in some contexts;
this has now been added to the list of reserved words.

8/10/2009 version 1.8.3

Remove redundant function strcmp: strncmp may be used with 
the third argument omitted, or strings can be compared for
equality directly.

Remove the temporary "set" variable "protect_lists".  Lists
given as arguments to user-defined functions are now
always protected.

Warning: although it's not recognized in the manual, we have
up till now accepted "end if" as an alias for the correct
termination of an "if" clause, namely "endif" (with no space).
This is slated for removal before long; please update scripts.

7/8/2009 version 1.8.2

No intentional backward-incompatible changes

5/21/2009 version 1.8.1

The default calculation method for the Hausman test in relation
to the random effects estimator has been reversed: we now use 
the regression method by default, and the matrix-difference 
method only if the --matrix-diff option is given.  For the 
present, the --hausman-reg option has been retained but it
does not really do anything, it just confirms the default.

The command "lmtest" has been renamed as "modtest".  However,
"lmtest" has been retained as an alias so this is not a
true incompatibility.

The gretl reference manual says that the names of gretl
commands are reserved, and cannot be used as the names of 
variables.  This has not been properly enforced in the past,
but it is now.

The exponentation operator, '^', now associates rightward,
which is how it works in most mathematical software: e.g.
2^2^3 = 2^(2^3) = 256.

1/23/2009 version 1.8.0

The obsolete command "rhodiff" as been removed.  To create
a quasi-differenced series (as rhodiff did), use the "genr"
command.

The obsolete mechanism "save=" for saving residuals and/or
fitted values from system estimation has been removed; please
use the accessors $uhat and $yhat for this purpose.

The matrices returned by the accessors $sigma and $vcv for VAR
systems now have a degrees of freedom correction.

9/28/2008 version 1.7.9

The "values" function no longer automatically truncates its 
argument (series or vector) to integer.  To get the old 
behavior for an argument x you should do values(int(x)).

Generation of monthly dummy variables: these dummies are
now named "dm1", "dm2", ... , "dm12".  Previously we tried
to use 3-letter abbreviations for the names of the months in
the current locale, but this is too error-prone given
different possible character encodings and (new) support
for languages that do not use the Roman character set.

8/28/2008 version 1.7.7

Ordered probit and logit: the presentation of the cut-points in
ordered response models is now that used by Stata and R, not
by William Greene as previously.  That is, we don't estimate a
generic constant, but report n-1 cut points, where n is the
number of response levels.

7/30/2008 version 1.7.6

List arguments to user-defined functions:

In the context of a "foreach" loop across such a list, the
accessor $i still gets the name of the variable at position i 
in the list, but the variable is not "visible" by that name
within the function.  To get a handle on the variable (e.g.
for use on the right-hand side of a genr command), use the
new syntax listname.varname.  See the chapter on functions in
the User's Guide for details.

6/12/2008 version 1.7.5

$sigma and $vcv accessors:

The $sigma and $vcv accessors have been changed for some model 
types. Now $sigma always refers to a measure associated with the 
residual variance, while $vcv always refer to the variance of
the parameter estimates.

In the case of VARs/VECMs, $vcv formerly referred to the cross-
equation covariance of the residuals.  Now $sigma is used for
that purpose; $vcv gets the variance of the coefficients, which
was not previously accessible.

logical operators:

We are now enforcing what the gretl manual has said for quite
some time: logical OR is represented by "||" and logical AND
by "&&".  The single "|" is now reserved for row-wise matrix
concatenation, and the single "&" for "taking the address of"
a variable.  Previously we tried to guess when "|" and "&" were
intended to represent OR and AND respectively, as in the
original gretl syntax, but no more.

3/21/2008 version 1.7.4

The old "multiply" command has been removed.

The old commands "corc", "hilu" and "pwe" are consolidated
into a new one, "ar1".  The old command words remain as
aliases but their use is deprecated.

2/29/2008 version 1.7.3

You cannot define a user-function having the same name as
a built-in function.