Solution : https://service.sap.com/sap/support/notes/63841 (SAP Service marketplace login required)
Summary : 
      This SAP Note provides detailed release information for the R/3 Add-On IS-Software across various versions. It distinguishes between installation and upgrade versions of the software, detailing specific releases from IS-SW Release 1.0 to 2.1 and IS-HT Release 4.61. Each release specifies compatibility with certain R/3 standard releases and outlines the available product numbers for installations and upgrades. Additionally, it discusses special cases in the upgrade process where direct transitions between standard SAP releases and IS-SW releases are not supported. The note also covers upgrade paths and compatibility issues, and concludes with information on supported languages and documentation.
Key words : 
-sw 21a product number cd51009425 viii, 0a        product number cd51005871 upgrade ga   2, 1a        product number cd51009141 vii, page high level introductory overview, 1a        product number gcd2u00i transport    1, 1a        product number gcd2n00i upgrade      1, 2a        product number gcf1n00i upgrade      1, 2a        product number gcf1u00i installation 1, 1a        product number cd51009144 installation 2, 0a        product number cd51005875 installation 2
Related Notes : 
       
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| 308120 | IS-HT Rel 4.61 and R/3 4.6B Add On Support Packages | 
| 208821 | Overview: Notes on R/3 Add-on DI | 
| 170144 | IS-SW Rel 2.0 and R/3 4.5B Add On Support Packages | 
| 165988 | Add info. for R/3 add-on upgrade IS-SW 2.0A GA | 
| 124850 | Additions to add-on Delta upgrade IS-SW 1.2D | 
| 96525 | IS-SW Rel 1.3 and R/3 3.1H Hot Packages | 
| 93297 | Additions to add-on Delta upgrade IS-SW 1.2C | 
| 89974 | Additional info. to Add-On Installation IS-SW 1.3A | 
| 86058 | Add information for R/3 add-on upgrade IS-SW 1.3A | 
| 80082 | IS-SW 1.2B Customizing Changes & CATT Notes | 
| 80078 | IS-SW Rel 1.2 and R/3 3.0F Hot Packages | 
| 79279 | Additions to add-on Delta upgrade IS-SW 1.2B | 
| 77293 | Applying Standard Notes to IS-Software | 
| 76177 | Missing customizing and master data in IS-SW 1.2A | 
| 74230 | Overview : Notes for Installation / Upgrade IS-SW | 
| 73622 | Additions to add-on Installation IS-SW 1.2A | 
| 73031 | Additional Customizing Req'd for IS-SW 1.2A | 
| 72972 | Add information for R/3 add-on upgrade IS-SW 1.2A | 
| 70195 | IS-SW and standard R/3 Hot Packages | 
| 68716 | IS-SW 1.1A Collective transport information | 
| 66606 | IS-SW Rel1.1 and R/3 3.0D/1 Hot packages | 
| 63548 | IS-SW 1.1A Customizing Installation Information | 
| 63126 | Additions to the R/3 add-on inst./upgr. IS-SW 1.1A | 
| 53902 | Conflicts between Support Packages and add-ons | 
| 13719 | Preliminary transports to customers (note for customers) | 
| 2857 | What table delivery classes are there? What is their signifi |