IELTS for UKVI is the new test approved by UK government and is commonly known as Secure English Language Test (SELT). No need to worry about the syllabus as the test taken is the same as IELTS (for all other purposes). The content, examiners, format, the level of difficulty, scoring, etc are exactly similar in case of IELTS for UKVI. The only difference is in the Test Report Forms that are slightly different, to give you a feel that you have taken the test at an IELTS UK visa session. Moreover, there are certain security protocols that are followed during IELTS for UKVI which are not implemented in case of the regular IELTS.
IELTS for UKVI is accepted by all other countries. One thing that you need to focus is being aware and updated as there can be certain changes by United Kingdom Visas and Immigration (UKVI). For this, you can keep consulting with IDP IELTS. Alongside, they provide all details related to the test so as to keep student worries at bay.