As we can see in the preceding diagram, there are many projects inside Spring Cloud and there are many relationships between them. By definition, these are all independent projects with different release cascades and version numbers. In a situation like this, dependency management in our application might be problematic and that will require knowledge about relationships between versions of all projects. To help make it easier, Spring Cloud introduced the starter mechanism, which we have already discussed, and release trains. The release trains are identified by names, not versions, to avoid confusion with the subprojects. What is interesting is that they are named after London tube stations and they are alphabetically ordered. The first release was Angel, the second was Brixton, and so on. The whole mechanism of dependency management is based on BOM (bill of materials), which is a standard Maven concept for managing artifacts versioned independently. Here's an actual table...
Argentina
Australia
Austria
Belgium
Brazil
Bulgaria
Canada
Chile
Colombia
Cyprus
Czechia
Denmark
Ecuador
Egypt
Estonia
Finland
France
Germany
Great Britain
Greece
Hungary
India
Indonesia
Ireland
Italy
Japan
Latvia
Lithuania
Luxembourg
Malaysia
Malta
Mexico
Netherlands
New Zealand
Norway
Philippines
Poland
Portugal
Romania
Russia
Singapore
Slovakia
Slovenia
South Africa
South Korea
Spain
Sweden
Switzerland
Taiwan
Thailand
Turkey
Ukraine
United States