Discuss changes in the following characteristics from one stage to another stage during the CSS life cycle model.
• 1.1. Staff expertise
-	During initial development the required expertise from the staff can change drastically due to the software changing itself
-	In the evolution phase there isn’t need for wide range of expertise but rather a deeper understanding of what they’re developing
-	In the servicing phase the expertise shift to servicing and maintenance. In essence, the staff needs to know how to keep the system running for their customers.
-	In the phaseout stage the you need expertise to devise and implement an exit strategy. These involves expertise on legacy systems and data migration.
• 1.2. Software architecture
-	The software architecture should be done in the initial development stage
-	In evolution phase changes are possible but more risky and costly
-	In the servicing stage you would need to reverse engineer the system and make it almost completely new, usually not worth it
-	In the phaseout stage there’s value in analysing the old system but focus should be on the new one.
• 1.3. Software decay
-	Following guidelines during development can reduce future decay
-	Code decay should be visible in the servicing phase making some changes unfeasible
-	High percentage of code decay can be a reason to initiate phaseout stage
• 1.4. Economics
-	Initial development is generally the time of investments and little income. With funding it might be different.
-	Economic reasons might drive design decisions
-	After the release of the software it should start to profit
-	Phaseout stage is generally initiated due to little profit from the system

How would each of the following groups use the information contained in a CR?
• 2.1 Maintainers
-	Identify the actual changes that the code requires
-	CR works as a guide for fixes
-	Communication between teams
• 2.2 Management
-	Keep track of the CRs to better understand the state of the system
-	Classification, statistics and analysis
-	Assign resources and employees
• 2.3 Quality and Test engineers
-	Reproducing the bug
-	Generate tests for the issues
-	Identify issues around the problem in the CR
• 2.4. Customers
-	Gain understanding about the system
-	Track their issues
-	Communication tool

3. (3-4) What is the difference between change propagation and change impact analysis?
-	Impact analysis focuses on single units and changes to determines what kind of effects it has.
-	Propagation aims to analyse changes throughout the system from a single change.