Telli, BenoumranSouid, Mohammed SaidStamova, Ivanka2023-01-202023-01-202023-01-12Axioms 12 (1): 80 (2023)https://hdl.handle.net/20.500.12588/1583This paper is devoted to boundary-value problems for Riemann–Liouville-type fractional differential equations of variable order involving finite delays. The existence of solutions is first studied using a Darbo's fixed-point theorem and the Kuratowski measure of noncompactness. Secondly, the Ulam–Hyers stability criteria are examined. All of the results in this study are established with the help of generalized intervals and piecewise constant functions. We convert the Riemann–Liouville fractional variable-order problem to equivalent standard Riemann–Liouville problems of fractional-constant orders. Finally, two examples are constructed to illustrate the validity of the observed results.Attribution 4.0 United Stateshttps://creativecommons.org/licenses/by/4.0/fractional differential equations of variable orderfinite delayboundary-value problemfixed-point theoremgreen functionUlam–Hyers stabilityArticle2023-01-20