Last year I applied for UK standard visitors Visa and was successfully issued, with Visa written at the top of the sticker which has the resemblance of the schengen Visa. Fast forward this year, in the month of June I applied for another standard visitors Visa but was issued an entry clearance sticker which has a different look than the regular Visa. I would like to know, at what point are this two stickers issued and under what circumstances? What are the major differences between them?
Several years ago, the EEA Member States introduced a uniform format visa vignette (a green coloured vignette, which all member states use). Unlike other Member States, the UK uses a different sticker for category D visas.
Uniform Format Visa (UFV).This vignette is common to all EU Member States. It is used for visa nationals coming to the UK as visitors or in transit (Category A, B or C)
United Kingdom Vignette. This is used for all other entry clearances (Category D), usually long-stay categories
An example of each vignette is available here: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/257789/examples-of-vignettes.pdf
You appear to have been given a Category D vignette.