Specialized Differences between Drupal 7 and Drupal 8

a.    Code Framework
Drupal 8 accompanies the Symfony system in which high performing PHP structure with improved code security.

Highlights of Symfony which help Drupal Developer:

• Multi-lingual: Symfony accompanies an in-constructed module called Translation. It handles language records and oversees site content in various dialects, making it simple to make multilingual sites.
• Serializer: This other part distributes the information in different arrangements from XML or JSON. 
• Routing: With directing, designers making page URLs web crawler amicable (SEO-accommodating URLs). This makes better-positioning sites on web crawlers.
• Object-Oriented Programming: Item Oriented Programming: Using object-situated programming ideas, Symfony executes different properties of OOPS ideas.

On the opposite side, Drupal 7 does not have an incredible structure to deal with its codebase, and having an absence of system highlights makes it harder to oversee code successfully.

Conclusion: Symfony structure makes Drupal 8 more grounded than Drupal 7 to create secure and hearty web applications.

b.    Template Engine
Drupal 7 uses the PHP layout as the default templating framework.

The clients make layouts by composing PHP code.

Drupal 8 uses Twig as a format engine. Twig is a piece of the Symfony 2 system and is a PHP-based ordered templating engine.
Here are a few contrasts between the composing formats inside Drupal 7 and 8:

Caching and compiling: When site page renders with Drupal 8, the Twig changes over the layout into an aggregated PHP format. After the accumulation, the layout documents are reserved for reuse. This takes into consideration quicker page access to site guests.