Recently I read in a web forum that the Aro lineage history is frequently revised. The implication was that it is an on-going work of fiction. You can easily check this for yourself. You will find it is untrue.
A version of the Aro lineage history was published in the journal Gassho in 1994. (Search for “Ngakpa” to find the article.) I compared it line-by-line with the current version on the Aro web site. You can do the same.
The versions are virtually identical. There are corrections of typos, tiny changes in wording, and changes to the English phonetic renderings of Tibetan words. (There is no generally-accepted system for representing Tibetan pronunciations using the Western alphabet.) The largest change is that the 1994 version uses Aro Lingma’s personal name (Yeshé Réma) rather than her tértön name (Aro Lingma). There are essentially no changes in the content.
If you suspected that intermediate versions might be significantly different from the earliest and latest version, you could check the “Wayback Machine.” This is a service that archives old versions of web sites. You can see its record of many versions of the Aro web site, at http://web.archive.org/web/*/http://aroter.org. I haven’t gone through them, because I don’t expect there have been significant changes to the history at any point. (If you find any, please leave a comment below.)