1.
How to start your application
modernisation journey
1

2.
2 Data classification. Published version. Owner’s name.
Last 10 years working in transformation
roles within Orange, EE and now with BT.
Worked as an architect and technical
lead within numerous transformation
projects as well as a joint venture and for
EE during BT purchase
Currently leading the modernisation of
BT’s application estate aligned to our
transformation objectives, driving
simplification and rationalisation of
applications
Steve Hawkins
Senior Manager Converged
Technology
BT’s Modernisation Journey
• BT’s Transformation
• Setting up the Tribe
• Refactoring Squad Structure
• Taking your first slice
• Scaling the work
• Lessons Learnt

3.
3
BT’s Transformation
• BT is driving towards major Public Cloud adoption
• The organisation is changing to a flatter more accountable structure
• Adopting modern methods to be more responsive to customer demands
• Pivoting to Tribes and squad structures to make faster better informed decisions with
empowered teams
• Accelerate transition to modern technology
• Remove complexity and legacy to reduce time to market
In order to remain relevant and competitive BT is modernizing the organization and
architecture

4.
4
BT’s Transformation in practical terms
Simplify the Architecture
Modernise the application estate
Establish a new Operating Model
Introduce Agile working practices
Remove Legacy
BT

5.
5 Data classification. Published version. Owner’s name.
Numerous teams across BT wanted to fully
understand the relationship between
network components, IT applications and
product variants in order to remove
legacy and cost.
Didn’t know how to start modernisation
Were hesitant about Public Cloud
The quality and completeness of
data about our estate needed
improving.
Problem Statement……
Many people are looking at
the same problem space.
Previous experience tells us that full closure of all connected
elements is difficult to achieve because unexpected
connections turn up due to the quality of the data about how
our estate is connected together.
It can take months of analysis to clearly understand the
potential impacts to the IT estate, and to find sources of
information.
The ability to realise cost savings is needed well-defined and
realisable plans.
Migrations needed traction and needed to have work aligned
across Tribes to realise removal outcomes.
Modernisation of the estate needed increased focus as an
enabler for the simplification of the estate

6.
Line of sight to Cost
and Plans
Work with key finance
teams to create a view of
IT Cost.
Create models to support
decision-making using
cost, value and
efficiencies.
Hold the overall plan of
which applications of the
estate are being
decommissioned / moved
to cloud and the timing of
each.
Knowledge
Repository
Build, maintain and
automate a data
repository to aggregate
application knowledge.
Establish ownership and
automation for data
sources.
Report on accuracy of the
estate based on key focus
areas.
Establish a Self Service
capability of the data.
Produce dashboards,
reports and detailed
technical insights into the IT
estate
Establish engagement with
external tribes to enable
working relationships to drive
opportunities for refactoring
and decommissioning and
build the backlog.
Early Deep Dive applications
for refactoring or
decommissioning
Maintain the front door for
the tribe.
Establish regular
communications to
stakeholders.
Engage with Value Streams
to build plans for execution
Opportunities
Specific squads will be set
up to deliver outcomes in
line with IT Transformation
targets.
Own and deliver against a
single, prioritised backlog for
decommissioning demand
in line with KPIs with a single
backlog.
Establish tiger teams to
accelerate
decommissioning
Decommissioning
Outcomes
Disaggregate legacy
applications into
microservices to support
Value Stream and Common
Component solutions and to
enable decommissioning
outcomes. Own the
refactoring backlog,
standards & design patterns.
Deliver against a single
prioritised backlog for all
SIMPLIFY refactoring
Build a community,
capabilities and patterns for
wider refactoring.
Establish and lead Public
Cloud refactoring aligning to
SIMPLIFY objectives.
Refactoring
Outcomes
Tribe Structure
What is a tribe in the context of the work ?
A model used within Spotify, a Tribe is a collection of squads that work to achieve the same outcomes

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Flow of work
• Utilise the EA roadmaps to categorise the estate
• Analyse the estate to establish the right group of
application
• Establish a selection criteria to isolate good
candidates
• Consider licences, 3rd parties, people costs and
where possible business benefits
• Build detailed understanding of each
application
• Execute refactoring – Determine your delivery
model
When dealing with a large application estate which needed a method to break down the estate into chunks
As candidates are reviewed in each of the squads there is a refinement which drops out poor candidates
Build Criteria and Decisioning to accelerate the assessment throughput
Refactoring
candidate
App3
App1
App2
Opportunities
Line of sight to cost and plans
Knowledge Repository
Refactoring

8.
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Refactoring Squad
Product
Owner
SA/Engineer
SA/Engineer
DevOps
Engineer
DevOps
Engineer
Product
Manager
Solution
Architect
Solution
Architect
Persistent squad
members
VMWare
team
Engineering teams
join the squad
Engineering teams
return to BAU
enabled
Core squad established with
team members that persist across
applications
Application specific engineers
from BAU team
VMWare ‘buddy-up’ to provide
consultancy and education on
the approach
BAU Teams return having carried
out refactoring
Team are educated and
experienced in Agile and
refactoring
Team can refactor and operate
using Agile framework
Transient squad
members

9.
9
Refactoring Technology Approach
Function 1
Current Platform
(Weblogic/Java)
Function 2
Function 3
Microservice 1
Microservice 2
Microservice 3
Target Platform
Kubernetes
Determine the best slice of the application
to refactor by analysing how the end to
end flow works
Determine the outcome value resulting from
refactoring
Build out microservices that
deliver a decoupled and resilient
service
Take a slice that is functionally
discrete and can be easily
refactored

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Scaling and CoE for Refactoring
Product
Owner
SA/Engineer
SA/Engineer
DevOps
Engineer
DevOps
Engineer
Product
Owner
SA/Engineer
SA/Engineer
Squad 1 Squad 2
Engineering teams
join the squad
Engineering teams
return to BAU
enabled
Establish multiple squads on a per
application basis
Establish a CoE squad to work
across the organisation and
establish best practices, patterns
and methods
Transient squad
members
Return to BAU enabled to operate
in an Agile framework and utilise
CI/CD pipeline deliveries

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Lessons Learned
• Don’t be afraid to try different approaches to refactoring to determine what works
• Changing the ‘Ways of Working’ is key and needs it’s own focus
• Establish a CoE for refactoring to build best practices and methods
• Functional alignment of the squads for refactoring brings stronger outcome benefits
• Ensure stakeholders continue to be aligned to the objectives of the refactoring
• Know the barriers that slow you down and be prepared to challenge them
• Use the big imperatives to accelerate the journey