diff --git a/CHANGELOG b/CHANGELOG
index 06b80ea..69ba6a0 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,4 +1,4 @@
-Version 0.8.3 prerelease
+Version 0.8.3 (2009.04.06):
     * fixed:   calculating the size of the main window
                now it looks good on MS Vista and when a user changes size of some
                widgets such as a border, font size, etc.
@@ -11,6 +11,7 @@ Version 0.8.3 prerelease
                previous were:
                medium - 192 bits for the mantissa, 64 bits for the exponent
                big    - 288 bits for the mantissa, 96 bits for the exponent
+    * changed: new version of TTMath bignum library: 0.8.3
     * added:   when a user presses CTRL+C then the result will be
                copied into the clipboard (if the current control which 
                has a focus is not an edit control, or if it is an edit
@@ -21,22 +22,57 @@ Version 0.8.3 prerelease
     * added:   'decimal point' option on the display tab
     * added:   variables and functions can have underline characters
                in their names
-    * added:   from TTMath 0.8.3: a short form of multiplication
-               (without the '*' character) e.g. '5y'
-               (it's used only if the second parameter is a variable
-               or function)
     * added:   'remove trailing zeroes' option on 'display' tab
     * added:   new language: spanish
                translation made by Alejandro S. Valdezate
                alesanval at gmail dot com
-    * added:   spanish language to the setup (installer)
-    * added:   the setup will remove mingwm10.dll if it exists in the program
-               directory
     * added:   on display tab: we can select 'deg' 'rad' or 'grad' for calculating
                in such functions: sin,cos,tan,cot,asin,acos,atan,acot
+    * added:   when the program exits new variables and functions are read from
+               the configuration file and then the file is saved
+               (if you have inserted some variables or functions in a different
+               instance of TTCalc those variables or functions were previously
+               skipped)
     * removed: 'cut off last non valid digits' on 'rounding' option
                on 'display' tab
 
+Changes from TTMath 0.8.3 relating to TTCalc:
+    * fixed:   Big::Add incorrectly rounded 'this' when both exponents were equal
+               it caused that sometimes when adding a zero the result has changed
+               this had impact among other things on FromString() method
+               "0,8" had different binary representation from "0,80"
+    * fixed:   Big::Pow(const Big<exp, man> & pow)
+               it's using PowInt() only when pow.exponent is in range (-man*TTMATH_BITS_PER_UINT; 0]
+               previously the powering 'hung' on an input like this: "(1+ 1e-10000) ^ 10e100000000"
+               (there was 10e100000000 iterations in PowInt())
+    * fixed:   in function DegToRad(const ValueType & x, ErrorCode * err = 0) it is better
+               to make division first and then mutliplication -- the result is more
+               accurate especially when x is: 90,180,270 or 360
+    * fixed:   the parser didn't correctly treat operators for changing the base
+               (radix) -- operators '#' and '&', e.g.:
+               '#sin(1)' was equal '0' -- there was a zero from '#' and then
+               it was multiplied by 'sin(1)'
+               the parser didn't check whether Big::FromString() has actually
+               read a proper value -- the method Big::FromString() didn't have
+               something to report such a situation
+    * fixed:   Big::FromString() when the base is 10, the method reads the scientific
+               part only if such a part it correctly supplied, e.g:
+               '1234e10', '1234e+10', '1234e-5'
+               previous '1234e' was treated as: '1234e0' (now parsing stops on 'e' and
+               the 'e' can be parsed by other parsers, e.g. the mathematical
+               parser -- now in the parser would be: '1234e' = '1234 * e' = '3354,3597...' )
+    * changed: in the parser: the form with operators '#' and '&' is as follows:
+               [-|+][#|&]numeric_value
+               previous was: [-|+][#|&][-|+]numeric_value
+    * changed: the parser is allowed to recognize values which
+               begin with a dot, e.g '.5' is treated as '0.5'
+    * added:   functions to the parser: gradtorad(grad), radtograd(rad), degtograd(deg),
+               degtograd(d,m,s), gradtodeg(grad)
+    * added:   a short form of multiplication
+               (without the '*' character) e.g. '5y'
+               (it's used only if the second parameter is a variable
+               or function)
+
 
 Version 0.8.2 portable (2007.07.01):
     * added:   the portable version of the program TTCalc
diff --git a/src/compileconfig.h b/src/compileconfig.h
index 22a1957..997c42f 100644
--- a/src/compileconfig.h
+++ b/src/compileconfig.h
@@ -56,7 +56,7 @@
 #define TTCALC_MAJOR_VER		0
 #define TTCALC_MINOR_VER		8
 #define TTCALC_REVISION_VER		3
-#define TTCALC_PRERELEASE_VER	1
+#define TTCALC_PRERELEASE_VER	0