http://delphi.wikia.com/wiki/CompilerVersion_Constant

The CompilerVersion constant identifies the internal version number of the Delphi compiler.

It is defined in the System unit and may be referenced either in code just as any other constant:

if CompilerVersion = 20 then

  sCompilerName := 'Delphi 2009';

or in conditional compiler expressions:

{$if CompilerVersion > 18}

  // Delphi 2007 or later

{$ifend}

The CompilerVersion constant was introduced in Delphi 6 along with conditional expressions.

In earlier Delphi versions various compiler defined VERxxx symbols are used to determine compiler versions.

CompilerVersion values and the equivalent compiler defined symbols for the Delphi versions in which the CompilerVersion constant is defined are:

Compiler
CompilerVersion

Defined Symbol

Delphi XE5
26
VER260

Delphi XE4
25
VER250

Delphi XE3
24
VER240

Delphi XE2
23
VER230

Delphi XE
22
VER220

Delphi 2010
21
VER210

Delphi 2009
20
VER200

Delphi 2007 .NET
19
VER190

Delphi 2007
18.5
VER185

Delphi 2006
18
VER180

Delphi 2005
17
VER170

Delphi 8 .NET
16
VER160

Delphi 7
15
VER150

Delphi 6
14
VER140

Delphi 5
13
VER130

Delphi 4
12
VER120

Delphi 3
10
VER100

Delphi 2
9
VER90

Delphi 1
8
VER80

http://delphi.wikia.com/wiki/Borland_Compiler_Conditional_Defines

Product Name
Version

Conditional Define

CompilerVersion

Embarcadero RAD Studio XE5
19.0
VER260
26

Embarcadero RAD Studio XE4
18.0
VER250
25

Embarcadero RAD Studio XE3
17.0
VER240
24

Embarcadero RAD Studio XE2
16.0
VER230
23

Embarcadero RAD Studio XE
15.0
VER220
22

Embarcadero RAD Studio 2010
14.0
VER210
21

CodeGear C++ Builder 2009
12.0
VER200
20

CodeGear Delphi 2007 for .NET
11.0
VER190
19?

CodeGear Delphi 2007 for Win32
11.0
VER180 and VER185
18, 18.5

Borland Developer Studio 2006
10.0
VER180
18

Borland Delphi 2005
9.0
VER170
17

Borland Delphi 8 for .NET
8.0
VER160 *
16

C++BuilderX
?
?

Borland C#Builder
1.0
VER160 *

Borland Delphi 7
7.0
VER150
15

Borland Kylix 3
3.0
VER140 **

Borland C++Builder 6
?
VER140 **(!!)

Borland Kylix 2
2.0
VER140 **

Borland Delphi 6
6.0
VER140 **
14

Borland Kylix
1.0
VER140 **

Borland C++Builder 5
?
VER130 ***

Borland Delphi 5
5.0
VER130 ***

Borland C++Builder 4
?
VER125

Borland Delphi 4
4.0
VER120

Borland C++Builder 3
?
VER110 ****

Borland Delphi 3
3.0
VER100

Borland C++ 5
?
?

Borland C++Builder 1
?
VER93

Borland Delphi 2
2.0
VER90

Borland C++ 4.5
?
?

Borland Delphi
1.0
VER80

Borland C++ 4
?
?

Borland Pascal 7
7.0
VER70

Borland C++ 3.1
?
?

Turbo Pascal for Windows 1.5
1.5
VER70

Turbo C++ for DOS 3
?
?

Borland C++ 3
?
?

Turbo C++ for Windows 3 (Win16)
?
?

Turbo Pascal for Windows 1.0
1.0
???

Borland C++ 2
?
?

Turbo Pascal 6
6.0
VER60

Turbo C++ for DOS
?
?

Turbo C for DOS 2
?
?

Turbo Pascal 5.5
5.5
VER55

Turbo C for DOS 1.5
?
?

Turbo Pascal 5
5.0
VER50

Turbo Pascal 4
4.0
VER40

Turbo C for DOS
?
?

Turbo Pascal 3
3.0
???

Turbo Pascal 2
2.0
???

Turbo Pascal 1
1.0
???

* This conditional define is shared by the Delphi compilers used to build C#Builder 1 and Delphi 8, which do not natively support Delphi for Win32.

This define is used in the "IDE Integration Packs" that were released to Borland partners in order to allow IDE plugins like ModelMaker Code Explorer

(http://www.modelmakertools.com/code-explorer/index.html) and

Castalia (http://www.delphi-expert.com/castalia3) to be compiled.

** This conditional define is shared between C++Builder 6, Delphi 6, Kylix 1, 2, and 3

(Checking for the conditional define "LINUX" helps to determine whether the compiler is Kylix or Delphi and "BCB" can be used to determine if C++Builder is being used).

*** This conditional define is shared with C++Builder 5

**** C++Builder 3.0 used VER110 (it had its own version of the Delphi compiler included).

**** CompilerVersion (Delphi 6 or later) can be used with conditional directives like

{$IF CompilerVersion >= 20}  {$DEFINE CanUnicode}  {$IFEND}

or using code:

if System.CompilerVersion >= 22 then  <do something>;